diff --git a/docs/guides/leaderboard.md b/docs/guides/leaderboard.md
index 5c58c30..c15c14b 100644
--- a/docs/guides/leaderboard.md
+++ b/docs/guides/leaderboard.md
@@ -92,11 +92,15 @@ of inferring one. GUIDs stay strings.
 | Highest round | Highest round reported with that player present, including players who joined mid-game. |
 | Total kills, headshots, revives, downs | Sum of each player's highest reported counter in each game. Round snapshots are cumulative, so they are never added together within a game. |
 | Total rounds | Round progression during observed participation, added across games. A player observed at game start and then round 8 receives seven rounds. A player first seen at round 8 gets a highest-round record of 8, but zero total rounds; reaching round 9 then adds one. |
-| Games played | Completed games in which a stats report at round 2 or later contains the player, even if they left before the end. Start-only and round 1 participation do not count. |
+| Games played | Completed games in which a stats report at round 2 or later contains the player, excluding players who left in the same round they joined. Staying through game end counts even without a round change. Legacy participation with an unknown joining round still counts. Start-only and round 1 participation do not count. |
 | Games completed | Games whose `game_end` roster contains the player. Disconnected players retain earlier stats without receiving completion credit. |
 | Best game kills | Highest kill count recorded in any one game. |
 | Highest reported score | Highest observed score balance. Spending points can lower the score, so this is not cumulative points earned. |
 
+Same-round departures retain their recorded stats, personal bests, and match
+history; only the games-played count excludes them. This also changes the game
+count used for efficiency qualification and per-game averages.
+
 Every ranking sorts highest first, including downs (a count, not an efficiency
 rating). Equal values share a rank; name and GUID provide a stable display order.
 Searching preserves the player's rank for the selected game/map filters, or
diff --git a/src/lib/server/fleet/leaderboard-participation.ts b/src/lib/server/fleet/leaderboard-participation.ts
new file mode 100644
index 0000000..48e1b67
--- /dev/null
+++ b/src/lib/server/fleet/leaderboard-participation.ts
@@ -0,0 +1,4 @@
+// Keep legacy participation countable when its joining round is unknown.
+// A player who stays through game end counts even without a round change.
+export const countsAsGamePlayed = `CASE WHEN mp.completed = 1 OR mp.first_observed_round IS NULL
+    OR mp.highest_round > mp.first_observed_round THEN 1 ELSE 0 END`;
diff --git a/src/lib/server/fleet/leaderboard.ts b/src/lib/server/fleet/leaderboard.ts
index e0c8d30..9f0b6df 100644
--- a/src/lib/server/fleet/leaderboard.ts
+++ b/src/lib/server/fleet/leaderboard.ts
@@ -1,6 +1,7 @@
 import { db } from '../db/index.js';
 import { MIN_RECORDED_ROUND } from '../../match-history.js';
 import { getPersonalBestRecords } from './leaderboard-records.js';
+import { countsAsGamePlayed } from './leaderboard-participation.js';
 import { EFFICIENCY_MIN_GAMES, EFFICIENCY_MIN_KILLS, EFFICIENCY_MIN_DOWNS,
     isEfficiencyMetric } from '../../leaderboard-efficiency.js';
 import { leaderboardMetrics, type LeaderboardEntry, type LeaderboardMap, type LeaderboardMetric,
@@ -74,6 +75,7 @@ function readLeaderboard(options: LeaderboardOptions, exactGuid?: string): Leade
     const aggregated = `WITH observations AS ${observationStorage} (
         SELECT mp.match_id, mp.guid, mp.highest_round, mp.kills, mp.rounds_survived,
             mp.headshots, mp.revives, mp.downs, mp.completed, mp.best_score, mp.last_seen_at,
+            ${countsAsGamePlayed} AS counts_as_game,
             m.started_at AS matchStartedAt, m.last_received_at AS matchUpdatedAt
         FROM leaderboard_match_players mp JOIN leaderboard_matches m ON m.id = mp.match_id
         WHERE ${conditions.join(' AND ')}
@@ -81,7 +83,7 @@ function readLeaderboard(options: LeaderboardOptions, exactGuid?: string): Leade
         SELECT guid, MAX(highest_round) AS highestRound,
             SUM(kills) AS kills, SUM(rounds_survived) AS roundsSurvived,
             SUM(headshots) AS headshots, SUM(revives) AS revives, SUM(downs) AS downs,
-            COUNT(*) AS gamesPlayed, SUM(completed) AS gamesCompleted,
+            SUM(counts_as_game) AS gamesPlayed, SUM(completed) AS gamesCompleted,
             MAX(kills) AS bestKills, MAX(best_score) AS bestScore, MAX(last_seen_at) AS lastSeen
         FROM observations GROUP BY guid
     ), measures AS (
diff --git a/src/lib/server/fleet/player-profile.ts b/src/lib/server/fleet/player-profile.ts
index 4ee3392..be5c8e4 100644
--- a/src/lib/server/fleet/player-profile.ts
+++ b/src/lib/server/fleet/player-profile.ts
@@ -1,11 +1,12 @@
 import { db } from '../db/index.js';
 import { MIN_RECORDED_ROUND } from '../../match-history.js';
 import { getPersonalBestRecords } from './leaderboard-records.js';
+import { countsAsGamePlayed } from './leaderboard-participation.js';
 import type { LeaderboardOptions, PlayerProfile, PlayerStats, PlayerMapRecord, PlayerMatch } from '../../leaderboard.js';
 
 const totals = `MAX(mp.highest_round) AS highestRound, SUM(mp.kills) AS kills,
     SUM(mp.rounds_survived) AS roundsSurvived, SUM(mp.headshots) AS headshots,
-    SUM(mp.revives) AS revives, SUM(mp.downs) AS downs, COUNT(*) AS gamesPlayed,
+    SUM(mp.revives) AS revives, SUM(mp.downs) AS downs, SUM(${countsAsGamePlayed}) AS gamesPlayed,
     SUM(mp.completed) AS gamesCompleted, MAX(mp.kills) AS bestKills, MAX(mp.best_score) AS bestScore`;
 const scope = `FROM leaderboard_match_players mp JOIN leaderboard_matches m ON m.id = mp.match_id
     WHERE m.game IN ('t5', 't6') AND m.status = 'completed' AND mp.guid = ? AND mp.has_stats = 1
@@ -20,8 +21,9 @@ export function getPlayerProfile(guid: string, requestedOffset = 0,
         WHERE game IN ('t5', 't6') AND guid = ? ORDER BY last_seen_at DESC, game LIMIT 1`)
         .get(guid) as Pick<PlayerProfile, 'guid' | 'name' | 'firstSeen' | 'lastSeen'> | undefined;
     if (!player) return null;
-    const stats = handle.prepare(`SELECT ${totals} ${scope}`).get(guid) as PlayerStats;
-    if (!stats.gamesPlayed) return null;
+    const { matchCount, ...stats } = handle.prepare(`SELECT COUNT(*) AS matchCount, ${totals} ${scope}`)
+        .get(guid) as PlayerStats & { matchCount: number };
+    if (!matchCount) return null;
     const historyParameters: Array<string | number> = [guid];
     let historyScope = scope;
     if (options.game) { historyScope += ' AND m.game = ?'; historyParameters.push(options.game); }
@@ -29,7 +31,7 @@ export function getPlayerProfile(guid: string, requestedOffset = 0,
     if (options.players) { historyScope += ' AND m.start_players = ?'; historyParameters.push(options.players); }
     const matchesTotal = options.game || options.map || options.players
         ? (handle.prepare(`SELECT COUNT(*) AS total ${historyScope}`).get(...historyParameters) as { total: number }).total
-        : stats.gamesPlayed;
+        : matchCount;
     const limit = 25;
     const lastOffset = Math.max(0, Math.floor((matchesTotal - 1) / limit) * limit);
     const offset = Number.isSafeInteger(requestedOffset) ? Math.min(lastOffset, Math.max(0, requestedOffset)) : 0;
diff --git a/src/routes/leaderboard/+page.svelte b/src/routes/leaderboard/+page.svelte
index 17b9e41..0e94129 100644
--- a/src/routes/leaderboard/+page.svelte
+++ b/src/routes/leaderboard/+page.svelte
@@ -28,7 +28,7 @@
         headshots: 'Cumulative headshots across recorded games.',
         revives: 'Cumulative teammates revived across recorded games.',
         downs: 'Cumulative downs across recorded games, ranked from most to fewest.',
-        gamesPlayed: 'Finished games with recorded player stats, including players who left before the end.',
+        gamesPlayed: 'Finished games with recorded player stats, excluding players who left in the same round they joined.',
         gamesCompleted: 'Games where the player appears in the final game-end report.',
         bestKills: 'The most kills reported for a player in a single game.',
         bestScore: 'The highest reported points balance. Spending points reduces this balance; it is not total points earned.'
diff --git a/tests/unit/leaderboard-efficiency-query.test.ts b/tests/unit/leaderboard-efficiency-query.test.ts
index 76c7abd..94e908b 100644
--- a/tests/unit/leaderboard-efficiency-query.test.ts
+++ b/tests/unit/leaderboard-efficiency-query.test.ts
@@ -141,3 +141,15 @@ it('accepts each efficiency metric through the API when the qualified group is e
             summary: { players: 1, matches: 4, kills: 80 } });
     }
 });
+
+it('does not use same-round departures to qualify for efficiency rankings', async () => {
+    const { db } = await import('../../src/lib/server/db/index.js');
+    addSamples(db(), 'short-visit', [...samples(4), { completed: 0 }]);
+    db().prepare(`UPDATE leaderboard_match_players SET first_observed_round = highest_round
+        WHERE completed = 0`).run();
+    const { getLeaderboard } = await import('../../src/lib/server/fleet/leaderboard.js');
+    expect(getLeaderboard().entries[0]).toMatchObject({ gamesPlayed: 4, gamesCompleted: 4,
+        kills: 100, averageKills: 25, completionRate: 1 });
+    const { efficiencyMetrics } = await import('../../src/lib/leaderboard-efficiency.js');
+    for (const { key } of efficiencyMetrics) expect(getLeaderboard({ metric: key }).entries).toEqual([]);
+});
diff --git a/tests/unit/leaderboard-ingest.test.ts b/tests/unit/leaderboard-ingest.test.ts
index b9864e0..8a662f0 100644
--- a/tests/unit/leaderboard-ingest.test.ts
+++ b/tests/unit/leaderboard-ingest.test.ts
@@ -269,6 +269,40 @@ it('keeps disconnected player records while completing only the final roster', a
         roundsSurvived: 3, gamesPlayed: 1, gamesCompleted: 0 }, matches: [{ status: 'completed', completed: 0 }] });
 });
 
+it.each([
+    [server, 'zombie_theater', 't5'],
+    ['t6_zombie_town_1', 'zm_transit', 't6']
+])('does not count same-round departures as games played on %s', async (source, map, game) => {
+    const { getLeaderboard } = await import('../../src/lib/server/fleet/leaderboard.js');
+    const { getPlayerProfile } = await import('../../src/lib/server/fleet/player-profile.js');
+    const departed = player('departed', { kills: 10 });
+    const advanced = player('advanced', { kills: 20 });
+    const finished = player('finished', { kills: 30 });
+    await report('game_start', 0, [], source, map);
+    await report('heartbeat', 5, [departed, advanced], source, map);
+    await report('heartbeat', 5, [player(departed.guid, { kills: 15 }), advanced], source, map);
+    await report('heartbeat', 5, [advanced], source, map);
+    await report('round_change', 6, [advanced, finished], source, map);
+    await report('game_end', 6, [finished], source, map);
+
+    const { closeDb } = await import('../../src/lib/server/db/index.js');
+    closeDb();
+    const board = getLeaderboard({ game });
+    expect(board.entries.find(entry => entry.guid === departed.guid)).toMatchObject({
+        gamesPlayed: 0, gamesCompleted: 0, kills: 15, highestRound: 5,
+        averageKills: null, averageRounds: null, completionRate: null
+    });
+    expect(board.entries.find(entry => entry.guid === advanced.guid)).toMatchObject({ gamesPlayed: 1, gamesCompleted: 0 });
+    expect(board.entries.find(entry => entry.guid === finished.guid)).toMatchObject({ gamesPlayed: 1, gamesCompleted: 1 });
+    const profile = getPlayerProfile(departed.guid)!;
+    expect(profile).toMatchObject({ stats: { gamesPlayed: 0, kills: 15 },
+        maps: [{ gamesPlayed: 0, kills: 15 }], matchesTotal: 1,
+        matches: [{ kills: 15, completed: 0 }], records: { bestKills: { value: 15 } } });
+    expect(getLeaderboard({ game, map: profile.maps[0].key, metric: 'gamesPlayed' }).entries)
+        .toContainEqual(expect.objectContaining({ guid: departed.guid, gamesPlayed: 0 }));
+    expect(getPlayerProfile(departed.guid, 0, { game, map: profile.maps[0].key })?.matchesTotal).toBe(1);
+});
+
 it('starts separate matches for game starts, map changes, round resets, and new rounds after an end', async () => {
     await report('game_start');
     await report('round_change', 5, [player(undefined, { kills: 50 })]);
diff --git a/tests/unit/leaderboard-query.test.ts b/tests/unit/leaderboard-query.test.ts
index bddb2db..a0b006b 100644
--- a/tests/unit/leaderboard-query.test.ts
+++ b/tests/unit/leaderboard-query.test.ts
@@ -387,6 +387,14 @@ describe('player profiles', () => {
         for (const offset of [-1, NaN, 0.5]) expect(getPlayerProfile('101', offset)?.offset).toBe(0);
         const { load } = await import('../../src/routes/leaderboard/players/[guid]/+page.server.js');
         expect((await load({ params: { guid: '101' }, url: new URL('http://localhost/leaderboard/players/101?offset=25') })).profile).toEqual(second);
+
+        // Historical same-round departures retain both pages even with no counted games.
+        handle.prepare(`UPDATE leaderboard_match_players SET first_observed_round = highest_round,
+            completed = 0 WHERE guid = '101'`).run();
+        const departures = getPlayerProfile('101', 25)!;
+        expect(departures).toMatchObject({ stats: { gamesPlayed: 0, kills: 770 }, matchesTotal: 34, offset: 25 });
+        expect(departures.matches).toHaveLength(9);
+        expect(departures.maps.every(map => map.gamesPlayed === 0)).toBe(true);
     });
 
     it('loads canonical profile URLs, encodes GUIDs and returns 404 for missing players', async () => {