diff --git a/SVSim.EmulatedEntrypoint/Services/MissionAssembler.cs b/SVSim.EmulatedEntrypoint/Services/MissionAssembler.cs
index faa2f2b3..d000b07b 100644
--- a/SVSim.EmulatedEntrypoint/Services/MissionAssembler.cs
+++ b/SVSim.EmulatedEntrypoint/Services/MissionAssembler.cs
@@ -9,15 +9,18 @@ public sealed class MissionAssembler : IMissionAssembler
     private readonly IMissionCatalogRepository _catalog;
     private readonly IViewerMissionRepository _viewerRepo;
     private readonly TimeProvider _time;
+    private readonly IGameCalendarService _calendar;
 
     public MissionAssembler(
         IMissionCatalogRepository catalog,
         IViewerMissionRepository viewerRepo,
-        TimeProvider time)
+        TimeProvider time,
+        IGameCalendarService calendar)
     {
         _catalog = catalog;
         _viewerRepo = viewerRepo;
         _time = time;
+        _calendar = calendar;
     }
 
     public async Task<MissionInfoDataDto> BuildAsync(Viewer viewer, CancellationToken ct = default)
@@ -54,15 +57,14 @@ public sealed class MissionAssembler : IMissionAssembler
             if (c.EventType is not null) counterEventKeys.Add(c.EventType);
         }
 
-        // BP monthly missions for current JST month.
-        var jstNow = now.ToOffset(TimeSpan.FromHours(9)).AddHours(-2);
-        var monthlyMissions = await _catalog.GetMonthlyMissionsAsync(jstNow.Year, jstNow.Month, ct);
+        // BP monthly missions for the current calendar month (UTC).
+        var monthlyMissions = await _catalog.GetMonthlyMissionsAsync(now.Year, now.Month, ct);
         foreach (var mm in monthlyMissions)
         {
             if (mm.EventType is not null) counterEventKeys.Add(mm.EventType);
         }
 
-        var periods = new[] { JstPeriod.DayKey(now), JstPeriod.WeekKey(now), JstPeriod.MonthKey(now), JstPeriod.AllTime };
+        var periods = _calendar.AllPeriods(now);
         var counters = counterEventKeys.Count == 0
             ? new List<ViewerEventCounter>()
             : await _viewerRepo.GetCountersAsync(viewer.Id, counterEventKeys.ToList(), periods, ct);
@@ -78,7 +80,7 @@ public sealed class MissionAssembler : IMissionAssembler
             int total = 0;
             if (cat.EventType is not null)
             {
-                string period = cat.LotType == 6 ? JstPeriod.DayKey(now) : JstPeriod.WeekKey(now);
+                string period = cat.LotType == 6 ? _calendar.DayKey(now) : _calendar.WeekKey(now);
                 total = GetCounter(cat.EventType, period);
             }
             dto.UserMissionList.Add(new UserMissionDto
@@ -105,7 +107,7 @@ public sealed class MissionAssembler : IMissionAssembler
         foreach (var a in viewerAchievements.OrderBy(a => a.AchievementType))
         {
             if (!achievementCatalogByKey.TryGetValue((a.AchievementType, a.Level), out var catalog)) continue;
-            int total = catalog.EventType is null ? 0 : GetCounter(catalog.EventType, JstPeriod.AllTime);
+            int total = catalog.EventType is null ? 0 : GetCounter(catalog.EventType, GameCalendarService.AllTime);
             int maxLevel = maxLevelByType.TryGetValue(a.AchievementType, out var ml) ? ml : a.Level;
             dto.UserAchievementList.Add(new UserAchievementDto
             {
@@ -142,7 +144,7 @@ public sealed class MissionAssembler : IMissionAssembler
         // BP monthly missions block — omit when no rows for current month.
         if (monthlyMissions.Count > 0)
         {
-            var startUtc = new DateTimeOffset(jstNow.Year, jstNow.Month, 1, 2, 0, 0, TimeSpan.FromHours(9));
+            var startUtc = new DateTimeOffset(now.Year, now.Month, 1, 0, 0, 0, TimeSpan.Zero);
             var endUtc = startUtc.AddMonths(1).AddSeconds(-1);
             dto.BattlePassMonthlyMission = new BPMonthlyMissionsDto
             {
@@ -151,7 +153,7 @@ public sealed class MissionAssembler : IMissionAssembler
                 MissionList = monthlyMissions.Select(mm =>
                 {
                     int done = mm.EventType is null ? 0
-                        : GetCounter(mm.EventType, JstPeriod.MonthKey(now));
+                        : GetCounter(mm.EventType, _calendar.MonthKey(now));
                     var entry = new BPMonthlyMissionDto
                     {
                         Name = mm.Name,
diff --git a/SVSim.EmulatedEntrypoint/Services/MissionProgressService.cs b/SVSim.EmulatedEntrypoint/Services/MissionProgressService.cs
index 8181dece..0d340f06 100644
--- a/SVSim.EmulatedEntrypoint/Services/MissionProgressService.cs
+++ b/SVSim.EmulatedEntrypoint/Services/MissionProgressService.cs
@@ -9,24 +9,27 @@ public sealed class MissionProgressService : IMissionProgressService
     private readonly IMissionCatalogRepository _catalog;
     private readonly IViewerMissionRepository _viewerRepo;
     private readonly TimeProvider _time;
+    private readonly IGameCalendarService _calendar;
 
     public MissionProgressService(
         SVSimDbContext db,
         IMissionCatalogRepository catalog,
         IViewerMissionRepository viewerRepo,
-        TimeProvider time)
+        TimeProvider time,
+        IGameCalendarService calendar)
     {
         _db = db;
         _catalog = catalog;
         _viewerRepo = viewerRepo;
         _time = time;
+        _calendar = calendar;
     }
 
     public async Task RecordEventAsync(long viewerId, IReadOnlyList<string> eventKeys, int delta = 1, CancellationToken ct = default)
     {
         if (eventKeys.Count == 0) return;
         var now = _time.GetUtcNow();
-        var periods = JstPeriod.AllPeriods(now);
+        var periods = _calendar.AllPeriods(now);
 
         // 1. Increment counters for every (key, period).
         foreach (var key in eventKeys)
@@ -50,7 +53,7 @@ public sealed class MissionProgressService : IMissionProgressService
                 var atLevel = catalogRows.FirstOrDefault(r => r.Level == viewerRow.Level);
                 if (atLevel is null || atLevel.EventType is null) continue;
 
-                var count = await _viewerRepo.GetCounterAsync(viewerId, atLevel.EventType, JstPeriod.AllTime, ct);
+                var count = await _viewerRepo.GetCounterAsync(viewerId, atLevel.EventType, GameCalendarService.AllTime, ct);
                 if (count >= atLevel.RequireNumber && viewerRow.AchievementStatus == 0)
                 {
                     viewerRow.AchievementStatus = 1;