diff --git a/docs/guides/metrics.md b/docs/guides/metrics.md
index 89735a9..908c8be 100644
--- a/docs/guides/metrics.md
+++ b/docs/guides/metrics.md
@@ -83,6 +83,40 @@ statistics do not establish lobby-hours, availability, or an autoscaling shortag
 Match statistics cover the selected period only and have no previous-period
 comparison.
 
+## Players over time
+
+The player chart uses the lobby chart's periods: hourly for 24 hours, and UTC-aligned
+24-hour periods for 7 or 30 days. Labels use the report timezone. **Unique players**
+counts distinct player GUIDs in every period overlapped by their recorded match
+participation, from first to last sighting. Multiple matches in one period count
+once, and the same GUID across Black Ops I and II is one player. Matches that began
+before the range still contribute participation inside it. These are recorded
+participants, not concurrent player counts or the lobby chart's player-hours.
+
+**New players** counts a GUID at its earliest recorded sighting across both games.
+Game and Map filters limit unique players to matching retained matches; new players
+count only when their original sighting was in a matching match. A regular's first
+visit to another map or game does not make them new again. Period boundaries belong
+to the following period; a sighting exactly at the range's end counts in the final
+period. Range totals count distinct GUIDs across the entire window independently:
+daily unique counts cannot be added to get the range total.
+
+Periods before the earliest retained match are gaps, not zero players. This history
+boundary is fleet-wide, so filtering to a quiet map does not hide recorded zeroes.
+The chart notes limited history and marks periods clipped by the selected range or
+the retained-history boundary with hollow points. Totals cover available history
+only. Select a point, use Left/Right or Home/End, or open **Inspect a period** for
+the exact interval and counts. **View exact time data** provides the same values
+in a keyboard-accessible table, with missing history shown as a dash.
+
+History begins when leaderboard recording started; earlier play cannot be recovered.
+Players already playing then count as new when first recorded. Participation spans
+do not prove continuous presence between reports, and unrecorded matches are absent.
+Match retention removes participation, which can shorten or leave holes in this
+history. The durable first-seen player identities survive retention, so removing an
+old match cannot make a returning player new again. The original map cannot be
+recovered from an expired match. The chart remains available without occupancy samples.
+
 ## Timeline and tables
 
 The timeline defaults to **Average lobbies running**, split into **With players**,
@@ -217,6 +251,14 @@ retains the recorded number of starts. Match scope uses the exact saved `game` a
 labels, and its time window uses the saved `started_at` timestamp. Occupancy
 collection and evidence timestamps remain independent of match history.
 
+`players` contains the separately deduplicated range totals `uniquePlayers` and
+`newPlayers`, plus `historyStartAt` (the earliest retained match, in epoch
+milliseconds). Every `points` entry also has `uniquePlayers`, `newPlayers`, and
+`playerHistoryPartial`. Counts before retained history are `null`; known periods
+with no scoped participation are zero. Player charts treat either `partial` or
+`playerHistoryPartial` as partial. Participation timestamp changes and durable
+first-seen identity changes invalidate the report cache.
+
 Map rows expose `noEmpty`, `availabilityObserved`, and
 `availabilityUnknown` durations, plus current `policy` context and
 `noEmptyAtMaximum` / `noEmptyBelowMaximum` durations. `pooledAvailability` combines
diff --git a/src/lib/metrics.ts b/src/lib/metrics.ts
index 3f1e713..2bf00ee 100644
--- a/src/lib/metrics.ts
+++ b/src/lib/metrics.ts
@@ -92,7 +92,18 @@ export interface RunningMetrics {
     capturedHours: number;
 }
 
-export interface MetricPoint extends Utilization {
+export interface PlayerCounts {
+    /** Distinct GUIDs, across games; null means this interval predates retained history. */
+    uniquePlayers: number | null;
+    newPlayers: number | null;
+}
+
+export interface PlayerMetrics extends PlayerCounts {
+    /** Global earliest retained match, independent of the selected game/map. */
+    historyStartAt: number | null;
+}
+
+export interface MetricPoint extends Utilization, PlayerCounts {
     /** UTC bucket boundary, including when the selected interval starts later. */
     at: number;
     startAt: number;
@@ -100,6 +111,8 @@ export interface MetricPoint extends Utilization {
     partial: boolean;
     /** Captured scope wall time, excluding collection gaps. */
     capturedHours: number;
+    /** Retained player history begins inside this period. */
+    playerHistoryPartial: boolean;
 }
 
 export interface PreviousMetrics {
@@ -164,6 +177,7 @@ export interface MetricsData {
     /** Distinct recorded names sampled in this scope/window, including zero elapsed time. */
     sampledServerCount: number;
     matches: MatchMetrics;
+    players: PlayerMetrics;
     autoscaling: AutoscalingMetrics;
     maps: MapMetrics[];
     points: MetricPoint[];
diff --git a/src/lib/server/db/migrations.ts b/src/lib/server/db/migrations.ts
index dc3bf14..52bb46a 100644
--- a/src/lib/server/db/migrations.ts
+++ b/src/lib/server/db/migrations.ts
@@ -7,6 +7,7 @@ import { migrateFileBlobs } from './file-blobs.js';
 import { installPerformanceIndexes } from './performance-indexes.js';
 import {
     installMetricsMatchRevisions,
+    installMetricsPlayerRevisions,
     installMetricsPolicyRevisions,
     installMetricsProvisioningRevisions,
     installReportRevisions
@@ -85,6 +86,11 @@ export const migrations: readonly Migration[] = [
         version: 15,
         name: 'metrics provisioning report revisions',
         run: installMetricsProvisioningRevisions
+    },
+    {
+        version: 16,
+        name: 'metrics player history and report revisions',
+        run: installMetricsPlayerRevisions
     }
 ];
 
diff --git a/src/lib/server/fleet/metrics-players.ts b/src/lib/server/fleet/metrics-players.ts
new file mode 100644
index 0000000..cd5c0a3
--- /dev/null
+++ b/src/lib/server/fleet/metrics-players.ts
@@ -0,0 +1,87 @@
+import { db } from '../db/index.js';
+import type { MetricPoint, MetricsScope, PlayerMetrics } from '../../metrics.js';
+
+/** Populate the shared periods from retained participation, independently of occupancy samples. */
+export function readPlayerMetrics(
+    scope: MetricsScope,
+    since: number,
+    now: number,
+    points: MetricPoint[]
+): PlayerMetrics {
+    const handle = db();
+    const nowIso = new Date(now).toISOString();
+    const sinceIso = new Date(since).toISOString();
+    const { first } = handle
+        .prepare('SELECT MIN(started_at) AS first FROM leaderboard_matches WHERE started_at <= ?')
+        .get(nowIso) as { first: string | null };
+    const historyStartAt = first === null ? null : Date.parse(first);
+    const periods = points.map((point) => {
+        const available =
+            historyStartAt !== null &&
+            (historyStartAt < point.endAt || (historyStartAt === now && point.endAt === now));
+        point.uniquePlayers = available ? 0 : null;
+        point.newPlayers = available ? 0 : null;
+        point.playerHistoryPartial = available && historyStartAt! > point.startAt;
+        return { unique: new Set<string>(), fresh: new Set<string>() };
+    });
+    if (historyStartAt === null) return { historyStartAt, uniquePlayers: null, newPlayers: null };
+
+    const conditions = [
+        'm.last_received_at >= ?',
+        'm.started_at <= ?',
+        'p.last_seen_at >= ?',
+        'p.first_seen_at <= ?'
+    ];
+    const params = [sinceIso, nowIso, sinceIso, nowIso];
+    if (scope.game !== null) {
+        conditions.push('m.game = ?');
+        params.push(scope.game);
+    }
+    if (scope.map !== null) {
+        conditions.push('m.map_name = ?');
+        params.push(scope.map);
+    }
+    // The match clock and participation PK bound this scan to recent matches.
+    // The GUID/first-seen index looks up the durable cross-game identity without
+    // reclassifying a returning player after their older matches expire.
+    const rows = handle
+        .prepare(
+            `SELECT p.guid, p.first_seen_at AS start, p.last_seen_at AS end,
+            (SELECT MIN(first_seen_at) FROM leaderboard_players WHERE guid=p.guid) AS firstSeen
+        FROM leaderboard_matches m JOIN leaderboard_match_players p ON p.match_id=m.id
+        WHERE ${conditions.join(' AND ')}`
+        )
+        .iterate(...params) as Iterable<{
+        guid: string;
+        start: string;
+        end: string;
+        firstSeen: string | null;
+    }>;
+    const unique = new Set<string>();
+    const fresh = new Set<string>();
+    for (const row of rows) {
+        const start = Date.parse(row.start);
+        const end = Date.parse(row.end);
+        if (!Number.isFinite(start) || !Number.isFinite(end) || end < start) continue;
+        unique.add(row.guid);
+        // Scope the original sighting, never the first later visit to this game/map.
+        const isNew =
+            row.firstSeen !== null && Date.parse(row.firstSeen) === start && start >= since;
+        if (isNew) fresh.add(row.guid);
+        for (let index = 0; index < points.length; index++) {
+            const point = points[index];
+            // Internal boundaries belong to the next period. Include a sighting
+            // exactly at the report's inclusive right edge in its final period.
+            const startsBeforeEnd = start < point.endAt || (start === now && point.endAt === now);
+            if (point.uniquePlayers === null || end < point.startAt || !startsBeforeEnd) continue;
+            periods[index].unique.add(row.guid);
+            if (isNew && start >= point.startAt) periods[index].fresh.add(row.guid);
+        }
+    }
+    for (let index = 0; index < points.length; index++) {
+        if (points[index].uniquePlayers === null) continue;
+        points[index].uniquePlayers = periods[index].unique.size;
+        points[index].newPlayers = periods[index].fresh.size;
+    }
+    return { historyStartAt, uniquePlayers: unique.size, newPlayers: fresh.size };
+}
diff --git a/src/lib/server/fleet/metrics.ts b/src/lib/server/fleet/metrics.ts
index 54bd3fe..41743d0 100644
--- a/src/lib/server/fleet/metrics.ts
+++ b/src/lib/server/fleet/metrics.ts
@@ -1,5 +1,6 @@
 import { fleetSettings } from '../settings.js';
 import { db } from '../db/index.js';
+import { readPlayerMetrics } from './metrics-players.js';
 import { ONLINE_MAX_MS } from '../../server-freshness.js';
 import { zombieMaps } from '../../map-aliases.js';
 import { readAutoscalingMetrics } from './metrics-autoscaling.js';
@@ -314,9 +315,13 @@ export function readMetrics(input: MetricsDays | MetricsQuery, now = Date.now())
             endAt: end,
             partial: start !== at || end !== at + bucketMs,
             capturedHours: 0,
+            uniquePlayers: null,
+            newPlayers: null,
+            playerHistoryPartial: false,
             ...emptyUtilization()
         });
     }
+    const players = readPlayerMetrics(scope, since, now, points);
 
     const cells: HeatmapCell[] = Array.from({ length: 7 * 24 }, (_, index) => ({
         weekday: Math.floor(index / 24),
@@ -517,6 +522,7 @@ export function readMetrics(input: MetricsDays | MetricsQuery, now = Date.now())
         summary,
         running,
         matches: matchMetrics(totalMatches),
+        players,
         autoscaling: autoscaling.summary,
         sampledServerCount: sampledServers.size,
         maps,
diff --git a/src/lib/server/reports/revisions.ts b/src/lib/server/reports/revisions.ts
index 661772a..18c0b97 100644
--- a/src/lib/server/reports/revisions.ts
+++ b/src/lib/server/reports/revisions.ts
@@ -1,5 +1,26 @@
 import type Database from 'better-sqlite3';
 
+/** Player trends also change when a participation interval extends into another period. */
+export function installMetricsPlayerRevisions(handle: Database.Database) {
+    handle.exec(`CREATE INDEX IF NOT EXISTS idx_leaderboard_players_guid_first_seen
+        ON leaderboard_players(guid,first_seen_at);
+        DROP TRIGGER IF EXISTS report_metrics_leaderboard_match_players_UPDATE;
+        CREATE TRIGGER report_metrics_leaderboard_match_players_UPDATE
+        AFTER UPDATE ON leaderboard_match_players
+        WHEN OLD.match_id IS NOT NEW.match_id OR OLD.guid IS NOT NEW.guid
+            OR OLD.first_seen_at IS NOT NEW.first_seen_at OR OLD.last_seen_at IS NOT NEW.last_seen_at
+        BEGIN UPDATE report_revisions SET revision=revision+1 WHERE topic='metrics'; END;`);
+    for (const action of ['INSERT', 'UPDATE', 'DELETE']) {
+        const condition =
+            action === 'UPDATE'
+                ? 'WHEN OLD.guid IS NOT NEW.guid OR OLD.first_seen_at IS NOT NEW.first_seen_at'
+                : '';
+        handle.exec(`CREATE TRIGGER IF NOT EXISTS report_metrics_leaderboard_players_${action}
+            AFTER ${action} ON leaderboard_players ${condition}
+            BEGIN UPDATE report_revisions SET revision=revision+1 WHERE topic='metrics'; END;`);
+    }
+}
+
 /** Provisioning outcomes remain report inputs even after the policy is removed. */
 export function installMetricsProvisioningRevisions(handle: Database.Database) {
     for (const table of ['server_deployments', 'provisioning_sources'])
diff --git a/src/lib/ui/components/metrics/MetricsPlayers.svelte b/src/lib/ui/components/metrics/MetricsPlayers.svelte
new file mode 100644
index 0000000..ef89fa9
--- /dev/null
+++ b/src/lib/ui/components/metrics/MetricsPlayers.svelte
@@ -0,0 +1,614 @@
+<script lang="ts">
+    import type { MetricPoint, MetricsDays, PlayerMetrics } from '$lib/metrics.js';
+    import { createTimeFormatter } from '$lib/time-zone.js';
+    import {
+        metricLobbyAxis,
+        metricNumber,
+        metricPeriodLabels,
+        metricPlayerPaths
+    } from '$ui/metrics.js';
+    import Button from '$ui/components/primitives/Button.svelte';
+    import Field from '$ui/components/primitives/Field.svelte';
+    import Select from '$ui/components/primitives/Select.svelte';
+
+    let {
+        points,
+        players,
+        days,
+        since,
+        timeZone
+    }: {
+        points: MetricPoint[];
+        players: PlayerMetrics;
+        days: MetricsDays;
+        since: number;
+        timeZone: string;
+    } = $props();
+    let selectedAt = $state<number | null>(null);
+    let announcement = $state('');
+    const format = $derived(createTimeFormatter(timeZone));
+    const selectedIndex = $derived.by(() => {
+        const existing = points.findIndex((point) => point.at === selectedAt);
+        if (existing >= 0) return existing;
+        for (let index = points.length - 1; index >= 0; index--)
+            if (!partial(points[index]) && points[index].uniquePlayers !== null) return index;
+        return Math.max(0, points.length - 1);
+    });
+    const selected = $derived(points[selectedIndex]);
+    const axis = $derived(
+        metricLobbyAxis(
+            Math.max(
+                0,
+                ...points.flatMap((point) => [point.uniquePlayers ?? 0, point.newPlayers ?? 0])
+            )
+        )
+    );
+    const uniquePath = $derived(
+        metricPlayerPaths(
+            points.map((point) => point.uniquePlayers),
+            axis.ceiling
+        )
+    );
+    const newPath = $derived(
+        metricPlayerPaths(
+            points.map((point) => point.newPlayers),
+            axis.ceiling
+        )
+    );
+    const periodLabels = $derived(metricPeriodLabels(points, days, timeZone));
+    const periodOptions = $derived(
+        points.map((point) => ({
+            value: String(point.at),
+            label: `${format.period(point.startAt)}${partial(point) ? ' · partial' : ''}${point.uniquePlayers === null ? ' · no retained history' : ''}`
+        }))
+    );
+    const limitedHistory = $derived(
+        players.historyStartAt !== null && players.historyStartAt > since
+    );
+
+    function partial(point: MetricPoint) {
+        return point.partial || point.playerHistoryPartial;
+    }
+    function count(value: number | null) {
+        return value === null ? '—' : metricNumber(value);
+    }
+    function summary(point: MetricPoint) {
+        return point.uniquePlayers === null
+            ? 'No retained player history'
+            : `${count(point.uniquePlayers)} unique players · ${count(point.newPlayers)} new`;
+    }
+    function selectPeriod(at: number) {
+        selectedAt = at;
+        const point = points.find((item) => item.at === at);
+        if (point)
+            announcement = `${format.period(point.startAt)} to ${format.period(point.endAt)}${partial(point) ? ', partial period' : ''}. ${summary(point)}`;
+    }
+    function move(direction: number) {
+        const point = points[Math.max(0, Math.min(points.length - 1, selectedIndex + direction))];
+        if (point) selectPeriod(point.at);
+    }
+    function chartKey(event: KeyboardEvent, index: number) {
+        if (!['ArrowLeft', 'ArrowRight', 'Home', 'End'].includes(event.key)) return;
+        event.preventDefault();
+        const next =
+            event.key === 'Home'
+                ? 0
+                : event.key === 'End'
+                  ? points.length - 1
+                  : Math.max(
+                        0,
+                        Math.min(points.length - 1, index + (event.key === 'ArrowLeft' ? -1 : 1))
+                    );
+        selectPeriod(points[next].at);
+        (event.currentTarget as HTMLElement).parentElement
+            ?.querySelectorAll<HTMLButtonElement>('button')
+            [next]?.focus();
+    }
+</script>
+
+<section class="panel" aria-labelledby="metrics-players-title">
+    <div class="heading">
+        <div>
+            <h2 id="metrics-players-title">Players over time</h2>
+            <p>
+                Distinct players seen in each {days === 1 ? 'hour' : '24-hour period'}, and players
+                seen for the first time. A returning player counts once per period.
+            </p>
+        </div>
+        <div class="totals">
+            <dl aria-label="Players across the selected range">
+                <div>
+                    <dt>Unique players</dt>
+                    <dd>{count(players.uniquePlayers)}</dd>
+                </div>
+                <div>
+                    <dt>New players</dt>
+                    <dd>{count(players.newPlayers)}</dd>
+                </div>
+            </dl>
+            <p>
+                Last {days === 1 ? '24 hours' : `${days} days`}{limitedHistory
+                    ? ' · Partial history'
+                    : ''}
+            </p>
+        </div>
+    </div>
+    <div class="legend">
+        <span><i class="unique-key"></i>Unique players</span>
+        <span><i class="new-key"></i>New players</span>
+        <span><i class="partial-key"></i>Partial period</span>
+    </div>
+    {#if players.historyStartAt === null}
+        <p class="history-note">
+            No retained player history yet. Counts will appear after match participation is
+            recorded.
+        </p>
+    {:else if limitedHistory}
+        <p class="history-note">
+            Retained player history starts {format.period(players.historyStartAt)}. Earlier periods
+            are gaps; range totals cover available history only.
+        </p>
+    {/if}
+    <div class="axis-title">Players</div>
+    <div class="chart-grid">
+        <div class="y-axis" aria-hidden="true">
+            {#each axis.ticks as value}<span style:top={`${(1 - value / axis.ceiling) * 100}%`}
+                    >{metricNumber(value)}</span
+                >{/each}
+        </div>
+        <div
+            class="plot"
+            role="group"
+            aria-label="Players by period. Select a point or use the period selector below."
+        >
+            <svg viewBox="0 0 100 100" preserveAspectRatio="none" aria-hidden="true">
+                {#each axis.ticks as value}<line
+                        x1="0"
+                        x2="100"
+                        y1={100 - (value / axis.ceiling) * 100}
+                        y2={100 - (value / axis.ceiling) * 100}
+                        class="grid-line"
+                    />{/each}
+                <path d={uniquePath.area} class="area" />
+                <path d={uniquePath.line} class="unique-line" />
+                <path d={newPath.line} class="new-line" />
+            </svg>
+            {#each points as point, index (point.at)}
+                <button
+                    type="button"
+                    class="period"
+                    class:selected={point.at === selected?.at}
+                    class:partial={partial(point)}
+                    tabindex={index === selectedIndex ? 0 : -1}
+                    aria-pressed={point.at === selected?.at}
+                    aria-label={`${format.period(point.startAt)}${partial(point) ? ', partial period' : ''}: ${summary(point)}`}
+                    title={`${format.period(point.startAt)} – ${format.period(point.endAt)}: ${summary(point)}`}
+                    onclick={() => selectPeriod(point.at)}
+                    onkeydown={(event) => chartKey(event, index)}
+                >
+                    {#if point.uniquePlayers !== null}<span
+                            class="dot unique-dot"
+                            style:top={`${100 - (point.uniquePlayers / axis.ceiling) * 100}%`}
+                        ></span>{/if}
+                    {#if point.newPlayers !== null}<span
+                            class="dot new-dot"
+                            style:top={`${100 - (point.newPlayers / axis.ceiling) * 100}%`}
+                        ></span>{/if}
+                </button>
+            {/each}
+        </div>
+        <div class="x-axis" class:with-dates={days === 30} aria-hidden="true">
+            {#each periodLabels as item}<span
+                    style:left={`${item.position}%`}
+                    title={format.period(points[item.index].startAt)}
+                    >{item.label}{#if item.date}<small>{item.date}</small>{/if}</span
+                >{/each}
+        </div>
+    </div>
+    <p class="period-note">
+        {days === 1 ? 'Hours' : 'Weekdays'} show when each period starts in {timeZone.replaceAll(
+            '_',
+            ' '
+        )}.{days === 1 ? '' : ' Daily periods are 24-hour windows.'} Partial periods contain less history.
+    </p>
+    {#if selected}
+        <div class="selection-summary" aria-label="Selected player period summary">
+            <time
+                >{format.period(selected.startAt)}{partial(selected)
+                    ? ' · Partial period'
+                    : ''}</time
+            ><span>{summary(selected)}</span>
+        </div>
+        <details>
+            <summary>Inspect a period</summary>
+            <div class="period-controls">
+                <div class="period-select">
+                    <Field label={`Inspect a player period · ${timeZone.replaceAll('_', ' ')}`}
+                        ><Select
+                            value={String(selected.at)}
+                            options={periodOptions}
+                            onchange={(event) =>
+                                selectPeriod(
+                                    Number((event.currentTarget as HTMLSelectElement).value)
+                                )}
+                        /></Field
+                    >
+                </div>
+                <div class="step-buttons">
+                    <Button size="sm" disabled={selectedIndex === 0} onclick={() => move(-1)}
+                        >← Previous</Button
+                    >
+                    <Button
+                        size="sm"
+                        disabled={selectedIndex === points.length - 1}
+                        onclick={() => move(1)}>Next →</Button
+                    >
+                </div>
+            </div>
+            <p class="readout" aria-label="Selected player period details">
+                {format.period(selected.startAt)} – {format.period(selected.endAt)}{partial(
+                    selected
+                )
+                    ? ' · Partial period'
+                    : ''}<br />{summary(selected)}{selected.playerHistoryPartial
+                    ? ' · Retained history begins during this period.'
+                    : ''}
+            </p>
+        </details>
+    {/if}
+    <span class="sr-only" role="status" aria-live="polite">{announcement}</span>
+    <details>
+        <summary>View exact time data</summary>
+        <!-- svelte-ignore a11y_no_noninteractive_tabindex (Scrollable tables must be reachable by keyboard.) -->
+        <div class="table-wrap" role="region" aria-label="Player time data" tabindex="0">
+            <table>
+                <caption
+                    >Players by period in {timeZone.replaceAll('_', ' ')}. A dash means no retained
+                    history.</caption
+                >
+                <thead
+                    ><tr
+                        ><th scope="col">Period</th><th scope="col">Unique players</th><th
+                            scope="col">New players</th
+                        ></tr
+                    ></thead
+                >
+                <tbody
+                    >{#each points as point (point.at)}<tr
+                            ><th scope="row"
+                                >{format.period(point.startAt)}<small
+                                    >to {format.period(point.endAt)}{partial(point)
+                                        ? ' · Partial'
+                                        : ''}{point.uniquePlayers === null
+                                        ? ' · No retained history'
+                                        : point.playerHistoryPartial
+                                          ? ' · History begins'
+                                          : ''}</small
+                                ></th
+                            ><td>{count(point.uniquePlayers)}</td><td>{count(point.newPlayers)}</td
+                            ></tr
+                        >{/each}</tbody
+                >
+            </table>
+        </div>
+    </details>
+    <p class="method-note">
+        Range totals count each player once, so period counts do not add up to the unique total.
+        “New” means first recorded across both games; players already playing when recording began
+        also count as new. Missing or expired matches cannot be reconstructed.
+    </p>
+</section>
+
+<style>
+    .panel {
+        background: var(--surface);
+        border: 1px solid var(--border-subtle);
+        border-radius: var(--radius-lg);
+        padding: var(--space-5);
+        min-width: 0;
+    }
+    h2 {
+        margin: 0;
+        font-size: var(--text-lg);
+    }
+    .heading {
+        display: flex;
+        flex-wrap: wrap;
+        justify-content: space-between;
+        gap: var(--space-4);
+    }
+    .heading > div:first-child {
+        flex: 1 1 280px;
+        min-width: 0;
+    }
+    .heading p {
+        margin: var(--space-2) 0 var(--space-4);
+        color: var(--text-secondary);
+        font-size: var(--text-sm);
+    }
+    .totals dl {
+        display: flex;
+        gap: var(--space-5);
+        margin: 0;
+    }
+    dt {
+        color: var(--text-secondary);
+        font-size: var(--text-xs);
+        text-transform: uppercase;
+    }
+    dd {
+        margin: var(--space-1) 0 0;
+        font-size: var(--text-xl);
+        font-weight: var(--weight-semibold);
+        font-variant-numeric: tabular-nums;
+    }
+    .totals p {
+        font-size: var(--text-xs);
+    }
+    .legend {
+        display: flex;
+        flex-wrap: wrap;
+        gap: var(--space-4);
+        font-size: var(--text-xs);
+    }
+    .legend span {
+        display: flex;
+        align-items: center;
+        gap: 6px;
+    }
+    .legend i {
+        display: block;
+        width: 16px;
+    }
+    .unique-key {
+        border-top: 2px solid var(--chart-active);
+    }
+    .new-key {
+        border-top: 2px dashed var(--text-secondary);
+    }
+    .legend .partial-key {
+        width: 8px;
+        height: 8px;
+        border: 1px solid var(--text-secondary);
+        border-radius: 50%;
+    }
+    .axis-title {
+        margin-top: var(--space-5);
+        font-size: var(--text-xs);
+        color: var(--text-tertiary);
+    }
+    .chart-grid {
+        display: grid;
+        grid-template-columns: 44px minmax(0, 1fr);
+        column-gap: 8px;
+        margin-top: 12px;
+    }
+    .y-axis {
+        position: relative;
+        height: 210px;
+        font-size: var(--text-xs);
+        color: var(--text-tertiary);
+    }
+    .y-axis span {
+        position: absolute;
+        right: 0;
+        transform: translateY(-50%);
+    }
+    .plot {
+        position: relative;
+        display: flex;
+        height: 210px;
+    }
+    svg {
+        position: absolute;
+        width: 100%;
+        height: 100%;
+        overflow: visible;
+        pointer-events: none;
+    }
+    svg path,
+    svg line {
+        vector-effect: non-scaling-stroke;
+    }
+    .grid-line {
+        stroke: var(--border-subtle);
+        stroke-width: 1;
+    }
+    .area {
+        fill: var(--chart-active);
+        opacity: 0.12;
+    }
+    .unique-line,
+    .new-line {
+        fill: none;
+        stroke-width: 2;
+    }
+    .unique-line {
+        stroke: var(--chart-active);
+    }
+    .new-line {
+        stroke: var(--text-secondary);
+        stroke-dasharray: 5 4;
+    }
+    .period {
+        position: relative;
+        flex: 1;
+        min-width: 0;
+        padding: 0;
+        margin: 0;
+        border: 0;
+        border-radius: 2px;
+        background: transparent;
+        cursor: pointer;
+    }
+    .period.selected {
+        background: color-mix(in srgb, var(--text-secondary) 6%, transparent);
+    }
+    .period:hover {
+        background: color-mix(in srgb, var(--chart-active) 10%, transparent);
+    }
+    .period:focus-visible {
+        outline: 2px solid var(--accent-primary-hover);
+        outline-offset: 3px;
+    }
+    .dot {
+        position: absolute;
+        left: 50%;
+        width: 7px;
+        height: 7px;
+        transform: translate(-50%, -50%);
+        border: 1px solid;
+        border-radius: 50%;
+        pointer-events: none;
+    }
+    .unique-dot {
+        background: var(--chart-active);
+        border-color: var(--chart-active);
+    }
+    .new-dot {
+        background: var(--text-secondary);
+        border-color: var(--text-secondary);
+    }
+    .partial .dot {
+        background: var(--surface);
+    }
+    .x-axis {
+        grid-column: 2;
+        position: relative;
+        min-width: 0;
+        height: 1.6em;
+        margin-top: 10px;
+        font-size: var(--text-xs);
+        color: var(--text-secondary);
+    }
+    .x-axis.with-dates {
+        height: 3em;
+    }
+    .x-axis > span {
+        position: absolute;
+        transform: translateX(-50%);
+        text-align: center;
+        white-space: nowrap;
+    }
+    small {
+        display: block;
+        color: var(--text-tertiary);
+        font-size: var(--text-xs);
+        font-weight: normal;
+        line-height: 1.5;
+    }
+    .period-note,
+    .method-note,
+    .history-note {
+        color: var(--text-secondary);
+        font-size: var(--text-xs);
+        line-height: var(--leading-body);
+        margin: var(--space-3) 0 0;
+    }
+    .history-note {
+        padding: var(--space-3);
+        border: 1px solid var(--border-subtle);
+        border-radius: var(--radius-sm);
+    }
+    .selection-summary {
+        display: flex;
+        flex-wrap: wrap;
+        gap: 8px 20px;
+        margin-top: var(--space-4);
+        font-size: var(--text-xs);
+        color: var(--text-secondary);
+    }
+    details {
+        margin-top: var(--space-4);
+        font-size: var(--text-sm);
+    }
+    summary {
+        cursor: pointer;
+        color: var(--text-secondary);
+        padding: 4px 0;
+    }
+    .period-controls {
+        display: flex;
+        flex-wrap: wrap;
+        align-items: flex-end;
+        gap: var(--space-3);
+        margin-top: var(--space-4);
+    }
+    .period-select {
+        flex: 1 1 250px;
+        max-width: 450px;
+    }
+    .step-buttons {
+        display: flex;
+        gap: var(--space-2);
+        padding-bottom: 3px;
+    }
+    .readout {
+        padding: var(--space-4);
+        border: 1px solid var(--border-subtle);
+        border-radius: var(--radius-md);
+        background: var(--surface-sunken);
+        color: var(--text-secondary);
+        font-size: var(--text-xs);
+        line-height: 1.6;
+    }
+    .table-wrap {
+        max-width: 100%;
+        overflow-x: auto;
+        margin-top: var(--space-3);
+    }
+    .table-wrap:focus-visible {
+        outline: 2px solid var(--accent-primary);
+        outline-offset: 3px;
+    }
+    table {
+        width: 100%;
+        border-collapse: collapse;
+        font-size: var(--text-xs);
+    }
+    caption {
+        text-align: left;
+        color: var(--text-tertiary);
+        margin-bottom: 8px;
+    }
+    th,
+    td {
+        padding: 12px;
+        border-bottom: 1px solid var(--border-subtle);
+        text-align: right;
+        white-space: nowrap;
+        font-variant-numeric: tabular-nums;
+    }
+    th:first-child {
+        text-align: left;
+    }
+    thead th {
+        color: var(--text-secondary);
+    }
+    tbody th {
+        font-weight: var(--weight-regular);
+    }
+    .sr-only {
+        position: absolute;
+        width: 1px;
+        height: 1px;
+        margin: -1px;
+        padding: 0;
+        overflow: hidden;
+        clip: rect(0, 0, 0, 0);
+        white-space: nowrap;
+        border: 0;
+    }
+    @media (max-width: 640px) {
+        .panel {
+            padding: var(--space-4);
+        }
+        .legend {
+            gap: 10px;
+        }
+        .chart-grid {
+            grid-template-columns: 32px minmax(0, 1fr);
+            column-gap: 6px;
+        }
+    }
+</style>
diff --git a/src/lib/ui/metrics-refresh.ts b/src/lib/ui/metrics-refresh.ts
index 105c5e2..46b9b78 100644
--- a/src/lib/ui/metrics-refresh.ts
+++ b/src/lib/ui/metrics-refresh.ts
@@ -32,6 +32,11 @@ const autoscaling = (value: unknown) =>
     ['readinessMeanSeconds', 'readinessMaxSeconds'].every(
         (key) => value[key] === null || nonnegative(value[key])
     );
+const players = (value: unknown) =>
+    record(value) &&
+    ['uniquePlayers', 'newPlayers'].every(
+        (key) => value[key] === null || (nonnegative(value[key]) && Number.isInteger(value[key]))
+    );
 const policy = (value: unknown) =>
     value === null ||
     (record(value) &&
@@ -51,6 +56,9 @@ function validReport(value: unknown): value is MetricsData {
         !totals(value.summary) ||
         !running(value.running) ||
         !matches(value.matches) ||
+        !record(value.players) ||
+        !players(value.players) ||
+        !timestamp(value.players.historyStartAt) ||
         !autoscaling(value.autoscaling)
     )
         return false;
@@ -95,6 +103,8 @@ function validReport(value: unknown): value is MetricsData {
                 numeric(item.startAt) &&
                 numeric(item.endAt) &&
                 nonnegative(item.capturedHours) &&
+                players(item) &&
+                typeof item.playerHistoryPartial === 'boolean' &&
                 typeof item.partial === 'boolean'
         )
     )
diff --git a/src/lib/ui/metrics.ts b/src/lib/ui/metrics.ts
index 0ee6da3..ad794a3 100644
--- a/src/lib/ui/metrics.ts
+++ b/src/lib/ui/metrics.ts
@@ -1,5 +1,31 @@
 const numberFormat = new Intl.NumberFormat('en-US', { maximumFractionDigits: 1 });
 
+/** Separate SVG paths at unavailable periods, including isolated recorded points. */
+export function metricPlayerPaths(values: readonly (number | null)[], ceiling: number) {
+    const segments: { x: number; y: number }[][] = [];
+    let segment: { x: number; y: number }[] = [];
+    for (let index = 0; index < values.length; index++) {
+        const value = values[index];
+        if (value === null) {
+            segment = [];
+            continue;
+        }
+        if (!segment.length) segments.push(segment);
+        segment.push({
+            x: ((index + 0.5) / values.length) * 100,
+            y: 100 - (value / ceiling) * 100
+        });
+    }
+    const line = (points: typeof segment) =>
+        points.map(({ x, y }, index) => `${index ? 'L' : 'M'}${x},${y}`).join(' ');
+    return {
+        line: segments.map(line).join(' '),
+        area: segments
+            .map((points) => `${line(points)} L${points.at(-1)!.x},100 L${points[0].x},100 Z`)
+            .join(' ')
+    };
+}
+
 /** Label the actual bucket start in the chosen timezone; never imply local calendar-day buckets. */
 export function metricPeriodLabels(
     points: readonly { startAt: number }[],
diff --git a/src/routes/metrics/+page.svelte b/src/routes/metrics/+page.svelte
index 1c8fe64..9e14975 100644
--- a/src/routes/metrics/+page.svelte
+++ b/src/routes/metrics/+page.svelte
@@ -19,6 +19,7 @@
     import Field from '$ui/components/primitives/Field.svelte';
     import Select from '$ui/components/primitives/Select.svelte';
     import MetricsChart from '$ui/components/metrics/MetricsChart.svelte';
+    import MetricsPlayers from '$ui/components/metrics/MetricsPlayers.svelte';
     import MetricsExplore from '$ui/components/metrics/MetricsExplore.svelte';
     import MetricsTables from '$ui/components/metrics/MetricsTables.svelte';
     import Freshness from '$ui/components/Freshness.svelte';
@@ -304,6 +305,13 @@
             </p>{/if}
         <MetricsChart points={report.points} days={report.days} timeZone={report.scope.timeZone} />
     {/if}
+    <MetricsPlayers
+        points={report.points}
+        players={report.players}
+        days={report.days}
+        since={report.since}
+        timeZone={report.scope.timeZone}
+    />
     {#if captured > 0}
         <MetricsHeatmap
             heatmap={report.heatmap}
diff --git a/tests/unit/database-migrations.test.ts b/tests/unit/database-migrations.test.ts
index e8f35c3..b16657c 100644
--- a/tests/unit/database-migrations.test.ts
+++ b/tests/unit/database-migrations.test.ts
@@ -206,6 +206,54 @@ it('adds match report invalidation on upgrade without invalidating for score hea
     expect(upgraded.prepare('SELECT * FROM leaderboard_match_players').all()).toEqual([]);
 });
 
+it('upgrades player report invalidation from version 15 for participation clocks and durable identities', async () => {
+    const { db, closeDb } = await import('../../src/lib/server/db/index.js');
+    const { installMetricsMatchRevisions } =
+        await import('../../src/lib/server/reports/revisions.js');
+    const handle = db();
+    handle.exec(
+        'DROP TRIGGER report_metrics_leaderboard_match_players_UPDATE; DROP INDEX idx_leaderboard_players_guid_first_seen'
+    );
+    for (const action of ['INSERT', 'UPDATE', 'DELETE'])
+        handle.exec(`DROP TRIGGER report_metrics_leaderboard_players_${action}`);
+    installMetricsMatchRevisions(handle);
+    handle.pragma('user_version = 15');
+    closeDb();
+    const upgraded = db();
+    const revision = () =>
+        (
+            upgraded
+                .prepare("SELECT revision FROM report_revisions WHERE topic='metrics'")
+                .get() as { revision: number }
+        ).revision;
+    upgraded.exec(`INSERT INTO leaderboard_matches
+        (id,server,game,map,map_key,map_name,started_at,last_received_at,last_event,last_fingerprint)
+        VALUES(1,'removed','t5','moon','moon','Moon','2026-10-10T12:00:00.000Z','2026-10-10T12:00:00.000Z','game_start','test');
+        INSERT INTO leaderboard_match_players(match_id,guid,first_seen_at,last_seen_at)
+        VALUES(1,'player','2026-10-10T12:00:00.000Z','2026-10-10T12:00:00.000Z');`);
+    let before = revision();
+    upgraded.exec("UPDATE leaderboard_match_players SET last_seen_at='2026-10-10T13:00:00.000Z'");
+    expect(revision()).toBeGreaterThan(before);
+    before = revision();
+    upgraded.exec(`INSERT INTO leaderboard_players(game,guid,name,first_seen_at,last_seen_at)
+        VALUES('t5','player','Player','2026-10-10T12:00:00.000Z','2026-10-10T13:00:00.000Z')`);
+    expect(revision()).toBeGreaterThan(before);
+    before = revision();
+    upgraded.exec(
+        "UPDATE leaderboard_players SET name='Renamed',last_seen_at='2026-10-10T14:00:00.000Z'"
+    );
+    expect(revision()).toBe(before);
+    upgraded.exec("UPDATE leaderboard_players SET first_seen_at='2026-10-09T12:00:00.000Z'");
+    expect(revision()).toBeGreaterThan(before);
+    expect(
+        upgraded
+            .prepare(
+                "SELECT name FROM sqlite_master WHERE name='idx_leaderboard_players_guid_first_seen'"
+            )
+            .get()
+    ).toBeDefined();
+});
+
 it('adds provisioning report invalidation at version 14 without invalidating for progress updates', async () => {
     const { db, closeDb } = await import('../../src/lib/server/db/index.js');
     const handle = db();
diff --git a/tests/unit/metrics-players.test.ts b/tests/unit/metrics-players.test.ts
new file mode 100644
index 0000000..800ecc8
--- /dev/null
+++ b/tests/unit/metrics-players.test.ts
@@ -0,0 +1,212 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { newFixture, type Fixture } from '../helpers/fixture.js';
+import type { MetricsDays } from '../../src/lib/metrics.js';
+
+let fixture: Fixture;
+beforeEach(async () => {
+    vi.resetModules();
+    fixture = await newFixture([]);
+});
+afterEach(async () => {
+    vi.restoreAllMocks();
+    await fixture.cleanup();
+});
+
+const hour = 3600_000;
+const day = 24 * hour;
+const now = Date.UTC(2026, 9, 10, 12, 30);
+const iso = (at: number) => new Date(at).toISOString();
+
+async function match(start: number, end: number, guids: string[], game = 't5', map = 'Moon') {
+    const { db } = await import('../../src/lib/server/db/index.js');
+    const handle = db();
+    const { lastInsertRowid: id } = handle
+        .prepare(
+            `INSERT INTO leaderboard_matches
+        (server,game,map,map_key,map_name,started_at,last_received_at,status,last_event,last_fingerprint)
+        VALUES ('removed-server',?,?,?, ?,?,?,'completed','game_end','test')`
+        )
+        .run(game, map, `${game}:${map}`, map, iso(start), iso(end));
+    for (const guid of guids) {
+        handle
+            .prepare(
+                `INSERT INTO leaderboard_match_players
+            (match_id,guid,first_seen_at,last_seen_at) VALUES(?,?,?,?)`
+            )
+            .run(id, guid, iso(start), iso(end));
+        handle
+            .prepare(
+                `INSERT INTO leaderboard_players(game,guid,name,first_seen_at,last_seen_at)
+            VALUES(?,?,?,?,?) ON CONFLICT(game,guid) DO UPDATE SET last_seen_at=excluded.last_seen_at`
+            )
+            .run(game, guid, guid, iso(start), iso(end));
+    }
+    return Number(id);
+}
+
+describe('metrics player history', () => {
+    it.each<MetricsDays>([1, 7, 30])(
+        'counts spans and repeated matches once per period and range for %i days',
+        async (days) => {
+            const { readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
+            const bucket = days === 1 ? hour : day;
+            const boundary = Math.floor((now - bucket) / bucket) * bucket;
+            await match(now - 40 * day, now - 40 * day, ['regular']);
+            await match(boundary - 10_000, boundary + 10_000, ['regular', 'newcomer']);
+            await match(boundary + 20_000, boundary + 30_000, ['regular', 'newcomer']);
+            const result = readMetrics(days, now);
+            const before = result.points.find((point) => point.at === boundary - bucket)!;
+            const after = result.points.find((point) => point.at === boundary)!;
+            expect(before).toMatchObject({ uniquePlayers: 2, newPlayers: 1 });
+            expect(after).toMatchObject({ uniquePlayers: 2, newPlayers: 0 });
+            expect(result.players).toMatchObject({ uniquePlayers: 2, newPlayers: 1 });
+            expect(result.points.reduce((sum, point) => sum + (point.uniquePlayers ?? 0), 0)).toBe(
+                4
+            );
+            expect(result.summary.observed).toBe(0);
+        }
+    );
+
+    it('uses participation rather than match start and includes both range endpoints', async () => {
+        const { readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
+        const since = now - day;
+        await match(since - 2 * hour, since - 1, ['ended-before']);
+        await match(since - hour, since + hour, ['spanning-start']);
+        await match(since, since, ['at-start']);
+        await match(now - hour, now + hour, ['spanning-end']);
+        await match(now, now, ['at-end']);
+        await match(now + 1, now + 1, ['future']);
+        const result = readMetrics(1, now);
+        expect(result.players).toMatchObject({ uniquePlayers: 4, newPlayers: 3 });
+        expect(result.points[0]).toMatchObject({ uniquePlayers: 2, newPlayers: 1, partial: true });
+        expect(result.points.at(-1)).toMatchObject({
+            uniquePlayers: 2,
+            newPlayers: 1,
+            partial: true
+        });
+    });
+
+    it('assigns a single sighting on an internal boundary only to the following period', async () => {
+        const { readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
+        await match(now - 2 * day, now - 2 * day, []);
+        const boundary = Date.UTC(2026, 9, 10, 11);
+        await match(boundary, boundary, ['boundary']);
+        const result = readMetrics(1, now);
+        expect(result.points.find((point) => point.at === boundary - hour)).toMatchObject({
+            uniquePlayers: 0,
+            newPlayers: 0
+        });
+        expect(result.points.find((point) => point.at === boundary)).toMatchObject({
+            uniquePlayers: 1,
+            newPlayers: 1
+        });
+        expect(result.points.find((point) => point.at === boundary + hour)).toMatchObject({
+            uniquePlayers: 0,
+            newPlayers: 0
+        });
+    });
+
+    it('deduplicates identity across games and scopes new players to their original match', async () => {
+        const { readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
+        await match(now - 2 * day, now - 2 * day, ['regular']);
+        await match(
+            now - 4 * hour,
+            now - 4 * hour,
+            ['both-games', 'regular'],
+            't6',
+            'Town Survival'
+        );
+        await match(now - 3 * hour, now - 3 * hour, ['both-games', 'regular', 'moon-new']);
+        await match(
+            now - 2 * hour,
+            now - 2 * hour,
+            ['moon-new', 'kino-new'],
+            't5',
+            'Kino Der Toten'
+        );
+        await match(now - hour, now - hour, ['town-new'], 't6', 'Town Survival');
+        await match(now - hour, now - hour, ['grief-new'], 't6', 'Town Grief');
+        const read = (game: string | null, map: string | null = null) =>
+            readMetrics({ days: 1, game, map, timeZone: 'UTC' }, now);
+        expect(read(null).players).toMatchObject({ uniquePlayers: 6, newPlayers: 5 });
+        expect(read('t5').players).toMatchObject({ uniquePlayers: 4, newPlayers: 2 });
+        expect(read('t5', 'Moon').players).toMatchObject({ uniquePlayers: 3, newPlayers: 1 });
+        expect(read('t5', 'Kino Der Toten').players).toMatchObject({
+            uniquePlayers: 2,
+            newPlayers: 1
+        });
+        expect(read('t6', 'Town Survival').players).toMatchObject({
+            uniquePlayers: 3,
+            newPlayers: 2
+        });
+        expect(read('t6', 'Town Grief').players).toMatchObject({ uniquePlayers: 1, newPlayers: 1 });
+        expect(read('t5', 'Missing').players).toMatchObject({ uniquePlayers: 0, newPlayers: 0 });
+        expect(read('t5', 'Missing').points.every((point) => point.uniquePlayers === 0)).toBe(true);
+    });
+
+    it('leaves periods before recording as gaps and marks the first retained period partial', async () => {
+        const { readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
+        const start = now - 2 * hour;
+        await match(start, start + 10_000, ['first']);
+        const result = readMetrics(1, now);
+        expect(result.players).toEqual({ historyStartAt: start, uniquePlayers: 1, newPlayers: 1 });
+        expect(
+            result.points
+                .filter((point) => point.endAt <= start)
+                .every((point) => point.uniquePlayers === null && point.newPlayers === null)
+        ).toBe(true);
+        expect(
+            result.points.find((point) => point.at === Math.floor(start / hour) * hour)
+        ).toMatchObject({
+            uniquePlayers: 1,
+            newPlayers: 1,
+            partial: false,
+            playerHistoryPartial: true
+        });
+        expect(result.points.at(-1)).toMatchObject({ uniquePlayers: 0, newPlayers: 0 });
+    });
+
+    it('moves the history bound after retention without making returning players new', async () => {
+        const { readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
+        const { db } = await import('../../src/lib/server/db/index.js');
+        const firstMatch = await match(now - 40 * day, now - 40 * day, ['regular']);
+        await match(now - day, now - day + hour, ['regular'], 't6', 'Town Survival');
+        db().prepare('DELETE FROM leaderboard_matches WHERE id=?').run(firstMatch);
+        const result = readMetrics(
+            { days: 30, game: 't6', map: 'Town Survival', timeZone: 'UTC' },
+            now
+        );
+        expect(result.players).toEqual({
+            historyStartAt: now - day,
+            uniquePlayers: 1,
+            newPlayers: 0
+        });
+        expect(result.points[0].uniquePlayers).toBeNull();
+        expect(db().prepare('SELECT COUNT(*) AS n FROM leaderboard_players').get()).toEqual({
+            n: 2
+        });
+    });
+
+    it('keeps no history unavailable, including when only durable player identities remain', async () => {
+        const { readMetrics } = await import('../../src/lib/server/fleet/metrics.js');
+        const { db } = await import('../../src/lib/server/db/index.js');
+        const assertMissing = () => {
+            const result = readMetrics(1, now);
+            expect(result.players).toEqual({
+                historyStartAt: null,
+                uniquePlayers: null,
+                newPlayers: null
+            });
+            expect(
+                result.points.every(
+                    (point) => point.uniquePlayers === null && point.newPlayers === null
+                )
+            ).toBe(true);
+        };
+        assertMissing();
+        await match(now - day, now - day, ['old']);
+        db().prepare('DELETE FROM leaderboard_matches').run();
+        await match(now + hour, now + hour, ['future']);
+        assertMissing();
+    });
+});
diff --git a/tests/unit/metrics-refresh.test.ts b/tests/unit/metrics-refresh.test.ts
index 12b7d00..62d27f5 100644
--- a/tests/unit/metrics-refresh.test.ts
+++ b/tests/unit/metrics-refresh.test.ts
@@ -18,6 +18,7 @@ const report = (days: number) => ({
     summary: totals,
     running: { average: null, peak: 0, capturedHours: 0 },
     matches: emptyMatches,
+    players: { uniquePlayers: null, newPlayers: null, historyStartAt: null },
     autoscaling: {
         added: 0,
         removed: 0,
@@ -286,11 +287,22 @@ describe('metrics background refresh', () => {
                     startAt: 0,
                     endAt: 1000,
                     partial: true,
+                    uniquePlayers: 0,
+                    newPlayers: 0,
+                    playerHistoryPartial: false,
                     capturedHours: 1 / 3600
                 }
             ]
         };
         const invalid = [
+            { ...value, players: undefined },
+            { ...value, players: { uniquePlayers: 1, newPlayers: 0 } },
+            ...[undefined, -1, 1.5, '2'].map((newPlayers) => ({
+                ...value,
+                players: { ...value.players, newPlayers }
+            })),
+            { ...value, points: [{ ...value.points[0], uniquePlayers: undefined }] },
+            { ...value, points: [{ ...value.points[0], playerHistoryPartial: undefined }] },
             { ...value, maps: [{ ...value.maps[0], running: undefined }] },
             {
                 ...value,
diff --git a/tests/unit/report-workers.test.ts b/tests/unit/report-workers.test.ts
index f2c9c9b..ffa620a 100644
--- a/tests/unit/report-workers.test.ts
+++ b/tests/unit/report-workers.test.ts
@@ -99,6 +99,32 @@ it('refreshes cached match metrics after active matches and recorded participant
     expect((await report()).scopeOptions).toEqual({ games: [], maps: [] });
 });
 
+it('refreshes player trends when participation crosses a period and first-seen identity changes', async () => {
+    const { db } = await import('../../src/lib/server/db/index.js');
+    const { metricsReport } = await import('../../src/lib/server/reports/index.js');
+    const now = Date.UTC(2026, 9, 10, 12, 30);
+    vi.spyOn(Date, 'now').mockReturnValue(now);
+    const query = parseMetricsQuery(new URLSearchParams('days=1'));
+    db().exec(`INSERT INTO leaderboard_matches
+        (id,server,game,map,map_key,map_name,started_at,last_received_at,last_event,last_fingerprint)
+        VALUES(1,'removed','t5','moon','moon','Moon','2026-10-10T11:30:00.000Z','2026-10-10T12:30:00.000Z','heartbeat','test');
+        INSERT INTO leaderboard_match_players(match_id,guid,first_seen_at,last_seen_at)
+        VALUES(1,'player','2026-10-10T11:30:00.000Z','2026-10-10T11:59:00.000Z');
+        INSERT INTO leaderboard_players(game,guid,name,first_seen_at,last_seen_at)
+        VALUES('t5','player','Player','2026-10-10T11:30:00.000Z','2026-10-10T11:59:00.000Z');`);
+    const first = await metricsReport(query);
+    expect(first.players).toMatchObject({ uniquePlayers: 1, newPlayers: 1 });
+    expect(first.points.at(-1)).toMatchObject({ uniquePlayers: 0, newPlayers: 0 });
+    db().exec("UPDATE leaderboard_match_players SET last_seen_at='2026-10-10T12:15:00.000Z'");
+    expect((await metricsReport(query)).points.at(-1)).toMatchObject({
+        uniquePlayers: 1,
+        newPlayers: 0
+    });
+    db().exec(`INSERT INTO leaderboard_players(game,guid,name,first_seen_at,last_seen_at)
+        VALUES('t6','player','Player','2026-10-01T11:30:00.000Z','2026-10-01T11:30:00.000Z')`);
+    expect((await metricsReport(query)).players).toMatchObject({ uniquePlayers: 1, newPlayers: 0 });
+});
+
 it('refreshes policy signals after policy edits and global pauses without new samples', async () => {
     const { db } = await import('../../src/lib/server/db/index.js');
     const { recordMetrics } = await import('../../src/lib/server/fleet/metrics.js');
diff --git a/tests/unit/ui-metrics-page.test.ts b/tests/unit/ui-metrics-page.test.ts
index 06f1a75..bf2a952 100644
--- a/tests/unit/ui-metrics-page.test.ts
+++ b/tests/unit/ui-metrics-page.test.ts
@@ -7,6 +7,7 @@ import MetricsAutoscaling from '../../src/lib/ui/components/metrics/MetricsAutos
 import MetricsTables from '../../src/lib/ui/components/metrics/MetricsTables.svelte';
 import MetricsExplore from '../../src/lib/ui/components/metrics/MetricsExplore.svelte';
 import MetricsChart from '../../src/lib/ui/components/metrics/MetricsChart.svelte';
+import MetricsPlayers from '../../src/lib/ui/components/metrics/MetricsPlayers.svelte';
 import { metricPage } from '../../src/lib/ui/metrics.js';
 import { page } from '$app/state';
 
@@ -66,6 +67,7 @@ function report(): MetricsData {
         scopeFirstSampleAt: now - 14 * 86400000,
         scopeLatestSampleAt: now,
         matches: matches(),
+        players: { uniquePlayers: 104, newPlayers: 70, historyStartAt: now - 14 * 86400000 },
         autoscaling: {
             added: 73,
             removed: 48,
@@ -86,6 +88,9 @@ function report(): MetricsData {
                 startAt: now - 86400000,
                 endAt: now,
                 partial: true,
+                uniquePlayers: 28,
+                newPlayers: 5,
+                playerHistoryPartial: false,
                 capturedHours: 1
             }
         ],
@@ -500,6 +505,68 @@ it('shows a global pause once while keeping Kino’s shortage ahead of quiet map
     expect(body).toContain('Consider raising the policy maximum');
 });
 
+it('renders player totals separately from periods with accessible selection, gaps and partial history', () => {
+    const data = report();
+    const original = data.points[0];
+    data.points = [
+        {
+            ...original,
+            at: original.at - 86400000,
+            startAt: original.startAt - 86400000,
+            endAt: original.startAt,
+            partial: false,
+            uniquePlayers: null,
+            newPlayers: null
+        },
+        { ...original, partial: false, playerHistoryPartial: true }
+    ];
+    data.players.historyStartAt = original.startAt + 3600000;
+    const body = render(MetricsPlayers, {
+        props: {
+            points: data.points,
+            players: data.players,
+            days: data.days,
+            since: data.since,
+            timeZone: data.scope.timeZone
+        }
+    }).body;
+    expect(body).toContain('Players over time');
+    expect(body).toContain('>104</dd>');
+    expect(body).toContain('>70</dd>');
+    expect(body).toContain('28 unique players · 5 new');
+    expect(body).toContain('Retained player history starts');
+    expect(body.replace(/\s+/g, ' ')).toContain('Earlier periods are gaps');
+    expect(body).toContain('Range totals count each player once');
+    expect(body).toContain('aria-label="Selected player period summary"');
+    expect(body).toContain('aria-label="Player time data" tabindex="0"');
+    expect(body).toContain('role="status"');
+    expect(body).toContain('View exact time data');
+    expect(body).toContain('No retained history');
+    const periods = body.match(/<button[^>]*class="period\b[\s\S]*?<\/button>/g) ?? [];
+    expect(periods).toHaveLength(2);
+    expect(periods[0]).not.toContain('class="dot');
+    expect(periods[1]).toContain('partial');
+    expect(periods[1]).toContain('tabindex="0"');
+    expect(body).not.toMatch(/<details[^>]*open/);
+});
+
+it('shows player trends without occupancy and shows unavailable counts when no match history remains', () => {
+    const data = report();
+    data.summary = { observed: 0, active: 0, idle: 0, unknown: 0, playerHours: 0 };
+    let body = render(MetricsPage, {
+        props: { data: { ...data, user: null, setupRequired: false } }
+    }).body;
+    expect(body).toContain('Players over time');
+    expect(body).toContain('>104</dd>');
+    data.players = { historyStartAt: null, uniquePlayers: null, newPlayers: null };
+    data.points = data.points.map((point) => ({ ...point, uniquePlayers: null, newPlayers: null }));
+    body = render(MetricsPage, {
+        props: { data: { ...data, user: null, setupRequired: false } }
+    }).body;
+    expect(body).toContain('No retained player history yet');
+    expect(body).toContain('>—</dd>');
+});
+
 it('keeps accessible chart selection, partial periods and gaps while collapsing inspection controls', () => {
     const data = report();
     data.points.push({
@@ -512,7 +579,10 @@ it('keeps accessible chart selection, partial periods and gaps while collapsing
         idle: 0,
         unknown: 0,
         playerHours: 0,
-        capturedHours: 0
+        capturedHours: 0,
+        uniquePlayers: null,
+        newPlayers: null,
+        playerHistoryPartial: false
     });
     const body = render(MetricsChart, {
         props: { points: data.points, days: data.days, timeZone: data.scope.timeZone }
diff --git a/tests/unit/ui-metrics.test.ts b/tests/unit/ui-metrics.test.ts
index df8d664..284b897 100644
--- a/tests/unit/ui-metrics.test.ts
+++ b/tests/unit/ui-metrics.test.ts
@@ -6,10 +6,17 @@ import {
     metricLobbyAxis,
     metricNumber,
     metricPercent,
-    metricPeriodLabels
+    metricPeriodLabels,
+    metricPlayerPaths
 } from '../../src/lib/ui/metrics.js';
 
 describe('metric presentation', () => {
+    it('breaks player lines at missing history while retaining real zeroes and isolated points', () => {
+        const paths = metricPlayerPaths([null, 2, 0, null, 1], 2);
+        expect(paths.line).toBe('M30,0 L50,100 M90,50');
+        expect(paths.area).toBe('M30,0 L50,100 L50,100 L30,100 Z M90,50 L90,100 L90,100 Z');
+        expect(metricPlayerPaths([null, null], 1)).toEqual({ line: '', area: '' });
+    });
     it('normalizes partial buckets by captured wall time and preserves unknown lobby counts', () => {
         expect(metricAverageLobbies(14 * 24, 24)).toBe(14);
         expect(metricAverageLobbies(14 * 0.5, 0.5)).toBe(14);