diff --git a/.claude/skills/add-contest-table-provider/instructions.md b/.claude/skills/add-contest-table-provider/instructions.md
index 5c3ee8062..8fbdd838d 100644
--- a/.claude/skills/add-contest-table-provider/instructions.md
+++ b/.claude/skills/add-contest-table-provider/instructions.md
@@ -33,16 +33,16 @@ Step 0 (seed check) is already done. Confirm the following before touching code:
 > Skip when an existing ContestType already covers this contest family (e.g. `AOJ_JAG` for JAG Prelim).
 
 - [ ] Add to `prisma/schema.prisma` ContestType enum → `pnpm exec prisma generate`
-- [ ] Add to `ContestType` in `src/lib/types/contest.ts` (same position as schema)
+- [ ] Add to `ContestType` in `src/lib/contests/types/contest.ts` (same position as schema)
 - [ ] `pnpm check` — confirm error resolved
 
 ## Layer 3 — Contest utilities (TDD)
 
 ### Tests first
 
-- [ ] Add exports to `src/test/lib/utils/test_cases/contest_type.ts` and `contest_name_labels.ts`
-- [ ] Add 3 `describe` blocks to `src/test/lib/utils/contest.test.ts`: classify / priority / name label
-- [ ] `pnpm test:unit src/test/lib/utils/contest.test.ts` — **RED**
+- [ ] Add exports to `src/lib/contests/fixtures/contest_type.ts` and `contest_name_labels.ts`
+- [ ] Add 3 `describe` blocks to `src/lib/contests/utils/contest.test.ts`: classify / priority / name label
+- [ ] `pnpm test:unit src/lib/contests/utils/contest.test.ts` — **RED**
 
 ### Implement
 
diff --git a/docs/guides/architecture.md b/docs/guides/architecture.md
index e78ccd92f..db684468c 100644
--- a/docs/guides/architecture.md
+++ b/docs/guides/architecture.md
@@ -158,6 +158,7 @@ src/lib/
 ├── clients/        # 外部 API クライアント（AtCoder Problems, AOJ）
 ├── components/     # 共通 UI コンポーネント（GradeLabel, TaskGradeList, TaskList, FormWrapper 等）
 ├── constants/      # アプリ定数
+├── contests/       # コンテスト分類・ラベル生成・優先度（types/, utils/, fixtures/）
 ├── server/         # サーバー専用の共有インフラ
 │   ├── database.ts # Prisma クライアント（14+ サービスが依存）
 │   ├── tasks/      # cache.ts など複数 feature 共有のサーバ処理
diff --git a/docs/guides/how-to-add-contest-table-provider.md b/docs/guides/how-to-add-contest-table-provider.md
index a8c68d045..70ef94fa9 100644
--- a/docs/guides/how-to-add-contest-table-provider.md
+++ b/docs/guides/how-to-add-contest-table-provider.md
@@ -6,8 +6,8 @@
 
 ## 事前確認
 
-- [ ] `ContestType`（`src/lib/types/contest.ts`）— 既存で対応できるか？複数 contest_id を統一表示するなら複合型
-- [ ] `classifyContest()`（`src/lib/utils/contest.ts`）— 新 contest_id に正しい ContestType を返すか
+- [ ] `ContestType`（`src/lib/contests/types/contest.ts`）— 既存で対応できるか？複数 contest_id を統一表示するなら複合型
+- [ ] `classifyContest()`（`src/lib/contests/utils/contest.ts`）— 新 contest_id に正しい ContestType を返すか
 - [ ] `prisma/tasks.ts` にデータが存在するか（複合型は `prisma/contest_task_pairs.ts` も）
 - [ ] 実装パターン判定（後述4パターン）
 - [ ] JOI: 2026 年より `joi{YYYY}ho` → `joi{YYYY}sf`。regex は `(ho|sf)` 対応済み
diff --git a/prisma/seed.ts b/prisma/seed.ts
index 9574a68ce..68a498fa3 100755
--- a/prisma/seed.ts
+++ b/prisma/seed.ts
@@ -24,7 +24,7 @@ import { hashPassword } from '../src/features/auth/server/password';
 import { getTaskGrade } from '../src/lib/types/task';
 import type { PlacementCreate } from '../src/features/workbooks/types/workbook_placement';
 
-import { classifyContest } from '../src/lib/utils/contest';
+import { classifyContest } from '../src/lib/contests/utils/contest';
 
 import { users, USER_PASSWORD_FOR_SEED } from './users';
 import { tasks } from './tasks';
diff --git a/src/features/tasks/types/contest-table/contest_table_provider.ts b/src/features/tasks/types/contest-table/contest_table_provider.ts
index 54b3ff251..83cc676e7 100644
--- a/src/features/tasks/types/contest-table/contest_table_provider.ts
+++ b/src/features/tasks/types/contest-table/contest_table_provider.ts
@@ -1,4 +1,4 @@
-import type { ContestType } from '$lib/types/contest';
+import type { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults, TaskResult } from '$lib/types/task';
 
 /**
diff --git a/src/features/tasks/utils/contest-table/abc_providers.test.ts b/src/features/tasks/utils/contest-table/abc_providers.test.ts
index ab0f1594f..651e00df5 100644
--- a/src/features/tasks/utils/contest-table/abc_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/abc_providers.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResult, TaskResults } from '$lib/types/task';
 
 import {
diff --git a/src/features/tasks/utils/contest-table/abc_providers.ts b/src/features/tasks/utils/contest-table/abc_providers.ts
index 2dea3fbc6..6dd8d795f 100644
--- a/src/features/tasks/utils/contest-table/abc_providers.ts
+++ b/src/features/tasks/utils/contest-table/abc_providers.ts
@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest, getContestNameLabel } from '$lib/utils/contest';
+import { classifyContest, getContestNameLabel } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/abs_provider.test.ts b/src/features/tasks/utils/contest-table/abs_provider.test.ts
index e86775812..54def4c19 100644
--- a/src/features/tasks/utils/contest-table/abs_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/abs_provider.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import { ABSProvider } from './abs_provider';
diff --git a/src/features/tasks/utils/contest-table/abs_provider.ts b/src/features/tasks/utils/contest-table/abs_provider.ts
index cf527e21a..12b9669e4 100644
--- a/src/features/tasks/utils/contest-table/abs_provider.ts
+++ b/src/features/tasks/utils/contest-table/abs_provider.ts
@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/utils/contest';
+import { classifyContest } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/acl_providers.test.ts b/src/features/tasks/utils/contest-table/acl_providers.test.ts
index 6cdc37388..c2c4b4826 100644
--- a/src/features/tasks/utils/contest-table/acl_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/acl_providers.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import { ACLPracticeProvider, ACLBeginnerProvider, ACLProvider } from './acl_providers';
diff --git a/src/features/tasks/utils/contest-table/acl_providers.ts b/src/features/tasks/utils/contest-table/acl_providers.ts
index 2235e0f9d..86ae9572f 100644
--- a/src/features/tasks/utils/contest-table/acl_providers.ts
+++ b/src/features/tasks/utils/contest-table/acl_providers.ts
@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/utils/contest';
+import { classifyContest } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/agc_provider.test.ts b/src/features/tasks/utils/contest-table/agc_provider.test.ts
index 83c91d730..c11600c68 100644
--- a/src/features/tasks/utils/contest-table/agc_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/agc_provider.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import { AGC001OnwardsProvider } from './agc_provider';
diff --git a/src/features/tasks/utils/contest-table/agc_provider.ts b/src/features/tasks/utils/contest-table/agc_provider.ts
index 93e0e0922..efb7703af 100644
--- a/src/features/tasks/utils/contest-table/agc_provider.ts
+++ b/src/features/tasks/utils/contest-table/agc_provider.ts
@@ -1,7 +1,7 @@
 import { type ContestTableMetaData } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest, getContestNameLabel } from '$lib/utils/contest';
+import { classifyContest, getContestNameLabel } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/aoj_icpc_providers.test.ts b/src/features/tasks/utils/contest-table/aoj_icpc_providers.test.ts
index ad709e1a2..046db0b88 100644
--- a/src/features/tasks/utils/contest-table/aoj_icpc_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/aoj_icpc_providers.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect, beforeEach, afterEach } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import { AOJ_LABEL_OVERRIDES } from './aoj_labels';
diff --git a/src/features/tasks/utils/contest-table/aoj_icpc_providers.ts b/src/features/tasks/utils/contest-table/aoj_icpc_providers.ts
index acd295bbf..92df296e4 100644
--- a/src/features/tasks/utils/contest-table/aoj_icpc_providers.ts
+++ b/src/features/tasks/utils/contest-table/aoj_icpc_providers.ts
@@ -1,4 +1,4 @@
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResult, TaskResults } from '$lib/types/task';
 import {
   type ContestTableMetaData,
diff --git a/src/features/tasks/utils/contest-table/aoj_jag_providers.test.ts b/src/features/tasks/utils/contest-table/aoj_jag_providers.test.ts
index d92f82509..5828d6025 100644
--- a/src/features/tasks/utils/contest-table/aoj_jag_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/aoj_jag_providers.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import { JagPrelimProvider } from './aoj_jag_providers';
diff --git a/src/features/tasks/utils/contest-table/aoj_jag_providers.ts b/src/features/tasks/utils/contest-table/aoj_jag_providers.ts
index 55bbfaf9b..e004f7193 100644
--- a/src/features/tasks/utils/contest-table/aoj_jag_providers.ts
+++ b/src/features/tasks/utils/contest-table/aoj_jag_providers.ts
@@ -1,4 +1,4 @@
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResult, TaskResults } from '$lib/types/task';
 import {
   type ContestTableMetaData,
diff --git a/src/features/tasks/utils/contest-table/arc_providers.test.ts b/src/features/tasks/utils/contest-table/arc_providers.test.ts
index 4a5ac472f..4acb3938e 100644
--- a/src/features/tasks/utils/contest-table/arc_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/arc_providers.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResult, TaskResults } from '$lib/types/task';
 
 import {
diff --git a/src/features/tasks/utils/contest-table/arc_providers.ts b/src/features/tasks/utils/contest-table/arc_providers.ts
index 2de4b2490..4751de367 100644
--- a/src/features/tasks/utils/contest-table/arc_providers.ts
+++ b/src/features/tasks/utils/contest-table/arc_providers.ts
@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest, getContestNameLabel } from '$lib/utils/contest';
+import { classifyContest, getContestNameLabel } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/awc_provider.test.ts b/src/features/tasks/utils/contest-table/awc_provider.test.ts
index 6306f96fa..99bd4e4b8 100644
--- a/src/features/tasks/utils/contest-table/awc_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/awc_provider.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import { AWCRangeProvider, AWCSpecialContestProvider } from './awc_provider';
diff --git a/src/features/tasks/utils/contest-table/awc_provider.ts b/src/features/tasks/utils/contest-table/awc_provider.ts
index 0a32cc731..0c9293ff6 100644
--- a/src/features/tasks/utils/contest-table/awc_provider.ts
+++ b/src/features/tasks/utils/contest-table/awc_provider.ts
@@ -2,10 +2,10 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest, getContestNameLabel } from '$lib/utils/contest';
+import { classifyContest, getContestNameLabel } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/axc_like_provider.test.ts b/src/features/tasks/utils/contest-table/axc_like_provider.test.ts
index 845bcaad6..3fba7b855 100644
--- a/src/features/tasks/utils/contest-table/axc_like_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/axc_like_provider.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import { ABCLikeProvider } from './axc_like_provider';
diff --git a/src/features/tasks/utils/contest-table/axc_like_provider.ts b/src/features/tasks/utils/contest-table/axc_like_provider.ts
index a46980471..d411d8be5 100644
--- a/src/features/tasks/utils/contest-table/axc_like_provider.ts
+++ b/src/features/tasks/utils/contest-table/axc_like_provider.ts
@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/utils/contest';
+import { classifyContest } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_base.test.ts b/src/features/tasks/utils/contest-table/contest_table_provider_base.test.ts
index c30191607..5dbdb797d 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_base.test.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_base.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 
 import { ABSProvider } from './contest_table_provider';
 import { taskResultsForABS } from '$features/tasks/fixtures/contest-table/contest_table_provider';
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_base.ts b/src/features/tasks/utils/contest-table/contest_table_provider_base.ts
index ef41ae617..fb36f1545 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_base.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_base.ts
@@ -5,7 +5,7 @@ import {
   type ContestTableDisplayConfig,
   type ProviderKey,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults, TaskResult } from '$lib/types/task';
 
 import { getTaskTableHeaderName } from '$lib/utils/task';
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_group.test.ts b/src/features/tasks/utils/contest-table/contest_table_provider_group.test.ts
index 46ce4d599..ac7aaeded 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_group.test.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_group.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 
 import {
   ABSProvider,
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_group.ts b/src/features/tasks/utils/contest-table/contest_table_provider_group.ts
index e16580a12..781b812bf 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_group.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_group.ts
@@ -1,5 +1,5 @@
 import { type ContestTablesMetaData } from '$features/tasks/types/contest-table/contest_table_provider';
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_groups.test.ts b/src/features/tasks/utils/contest-table/contest_table_provider_groups.test.ts
index 77372acb4..f879b1efd 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_groups.test.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_groups.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 
 import { TESSOKU_SECTIONS } from '$features/tasks/types/contest-table/contest_table_provider';
 
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_groups.ts b/src/features/tasks/utils/contest-table/contest_table_provider_groups.ts
index ea311d973..98e7da299 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_groups.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_groups.ts
@@ -1,4 +1,4 @@
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 
 import { ABSProvider } from './abs_provider';
 import {
diff --git a/src/features/tasks/utils/contest-table/dp_providers.test.ts b/src/features/tasks/utils/contest-table/dp_providers.test.ts
index 92cc9407c..c88cd189c 100644
--- a/src/features/tasks/utils/contest-table/dp_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/dp_providers.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import { EDPCProvider, TDPCProvider, NDPCProvider } from './dp_providers';
diff --git a/src/features/tasks/utils/contest-table/dp_providers.ts b/src/features/tasks/utils/contest-table/dp_providers.ts
index 8ee49b01f..9936ec050 100644
--- a/src/features/tasks/utils/contest-table/dp_providers.ts
+++ b/src/features/tasks/utils/contest-table/dp_providers.ts
@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/utils/contest';
+import { classifyContest } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/fps24_provider.test.ts b/src/features/tasks/utils/contest-table/fps24_provider.test.ts
index b1aeb2f0a..a520a86ae 100644
--- a/src/features/tasks/utils/contest-table/fps24_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/fps24_provider.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import { FPS24Provider } from './fps24_provider';
diff --git a/src/features/tasks/utils/contest-table/fps24_provider.ts b/src/features/tasks/utils/contest-table/fps24_provider.ts
index 48b5decee..488669c77 100644
--- a/src/features/tasks/utils/contest-table/fps24_provider.ts
+++ b/src/features/tasks/utils/contest-table/fps24_provider.ts
@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/utils/contest';
+import { classifyContest } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/joi_providers.test.ts b/src/features/tasks/utils/contest-table/joi_providers.test.ts
index 16e18ae21..46e7cfd99 100644
--- a/src/features/tasks/utils/contest-table/joi_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/joi_providers.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import {
@@ -81,7 +81,7 @@ describe('JOIFirstQualRoundProvider', () => {
   test('expects to handle invalid contest IDs gracefully', () => {
     const provider = new JOIFirstQualRoundProvider(ContestType.JOI);
 
-    expect(provider.getContestRoundLabel('invalid-id')).toBe('INVALID-ID'); // See: getContestNameLabel() in src/lib/utils/contest.ts
+    expect(provider.getContestRoundLabel('invalid-id')).toBe('INVALID-ID'); // See: getContestNameLabel() in src/lib/contests/utils/contest.ts
     expect(provider.getContestRoundLabel('joi2024yo1d')).toBe('2024d'); // 'd' doesn't match valid round (a|b|c)
   });
 
diff --git a/src/features/tasks/utils/contest-table/joi_providers.ts b/src/features/tasks/utils/contest-table/joi_providers.ts
index 9e78c1257..950ae6841 100644
--- a/src/features/tasks/utils/contest-table/joi_providers.ts
+++ b/src/features/tasks/utils/contest-table/joi_providers.ts
@@ -4,10 +4,10 @@ import {
   JOI_SECOND_QUAL_ROUND_SECTIONS,
   JOI_FINAL_ROUND_SECTIONS,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest, getContestNameLabel } from '$lib/utils/contest';
+import { classifyContest, getContestNameLabel } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/math_and_algorithm_provider.test.ts b/src/features/tasks/utils/contest-table/math_and_algorithm_provider.test.ts
index 2471ddae6..c972d89da 100644
--- a/src/features/tasks/utils/contest-table/math_and_algorithm_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/math_and_algorithm_provider.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import { MathAndAlgorithmProvider } from './math_and_algorithm_provider';
diff --git a/src/features/tasks/utils/contest-table/math_and_algorithm_provider.ts b/src/features/tasks/utils/contest-table/math_and_algorithm_provider.ts
index ed51c2248..51e175562 100644
--- a/src/features/tasks/utils/contest-table/math_and_algorithm_provider.ts
+++ b/src/features/tasks/utils/contest-table/math_and_algorithm_provider.ts
@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/utils/contest';
+import { classifyContest } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/tessoku_book_providers.test.ts b/src/features/tasks/utils/contest-table/tessoku_book_providers.test.ts
index 2bf3dc1d7..68241da1d 100644
--- a/src/features/tasks/utils/contest-table/tessoku_book_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/tessoku_book_providers.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import {
diff --git a/src/features/tasks/utils/contest-table/tessoku_book_providers.ts b/src/features/tasks/utils/contest-table/tessoku_book_providers.ts
index 4a32554cc..c11ae6e78 100644
--- a/src/features/tasks/utils/contest-table/tessoku_book_providers.ts
+++ b/src/features/tasks/utils/contest-table/tessoku_book_providers.ts
@@ -3,10 +3,10 @@ import {
   type ContestTableDisplayConfig,
   TESSOKU_SECTIONS,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/utils/contest';
+import { classifyContest } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/typical90_provider.test.ts b/src/features/tasks/utils/contest-table/typical90_provider.test.ts
index 6b03018df..a81473674 100644
--- a/src/features/tasks/utils/contest-table/typical90_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/typical90_provider.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResults } from '$lib/types/task';
 
 import { Typical90Provider } from './typical90_provider';
diff --git a/src/features/tasks/utils/contest-table/typical90_provider.ts b/src/features/tasks/utils/contest-table/typical90_provider.ts
index 86d5b9009..9afd35298 100644
--- a/src/features/tasks/utils/contest-table/typical90_provider.ts
+++ b/src/features/tasks/utils/contest-table/typical90_provider.ts
@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/utils/contest';
+import { classifyContest } from '$lib/contests/utils/contest';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/workbooks/components/detail/WorkBookTasksTable.svelte b/src/features/workbooks/components/detail/WorkBookTasksTable.svelte
index 1e2d32bf0..71d62dccd 100644
--- a/src/features/workbooks/components/detail/WorkBookTasksTable.svelte
+++ b/src/features/workbooks/components/detail/WorkBookTasksTable.svelte
@@ -14,7 +14,7 @@
   import GradeLabel from '$lib/components/GradeLabel.svelte';
   import ExternalLinkWrapper from '$lib/components/ExternalLinkWrapper.svelte';
 
-  import { addContestNameToTaskIndex } from '$lib/utils/contest';
+  import { addContestNameToTaskIndex } from '$lib/contests/utils/contest';
   import { getTaskUrl, removeTaskIndexFromTitle } from '$lib/utils/task';
 
   import type {
diff --git a/src/lib/clients/aizu_online_judge/clients.test.ts b/src/lib/clients/aizu_online_judge/clients.test.ts
index ed66b1228..0c1039688 100644
--- a/src/lib/clients/aizu_online_judge/clients.test.ts
+++ b/src/lib/clients/aizu_online_judge/clients.test.ts
@@ -11,7 +11,7 @@ import { Cache } from '$lib/clients/cache';
 
 import { AojCoursesApiClient, AojChallengesApiClient } from './clients';
 
-import type { ContestsForImport } from '$lib/types/contest';
+import type { ContestsForImport } from '$lib/contests/types/contest';
 import type { TasksForImport } from '$lib/types/task';
 import type { AOJCourseAPI, AOJChallengeContestAPI, AOJTaskAPIs } from './types';
 
diff --git a/src/lib/clients/aizu_online_judge/clients.ts b/src/lib/clients/aizu_online_judge/clients.ts
index 33fbc44e9..9af340fdd 100644
--- a/src/lib/clients/aizu_online_judge/clients.ts
+++ b/src/lib/clients/aizu_online_judge/clients.ts
@@ -2,7 +2,7 @@ import { HttpRequestClient } from '$lib/clients/http_client';
 import { ContestTaskCache } from '$lib/clients/cache_strategy';
 import { getCachedOrFetchContests, getCachedOrFetchTasks } from '$lib/clients/contest_task_fetcher';
 
-import type { ContestsForImport } from '$lib/types/contest';
+import type { ContestsForImport } from '$lib/contests/types/contest';
 import type { TasksForImport } from '$lib/types/task';
 
 import type {
diff --git a/src/lib/clients/aizu_online_judge/utils.ts b/src/lib/clients/aizu_online_judge/utils.ts
index 149464eb4..cb22863f7 100644
--- a/src/lib/clients/aizu_online_judge/utils.ts
+++ b/src/lib/clients/aizu_online_judge/utils.ts
@@ -1,4 +1,4 @@
-import type { ContestForImport } from '$lib/types/contest';
+import type { ContestForImport } from '$lib/contests/types/contest';
 
 import { PENDING } from './types';
 import type { AOJTaskAPI } from './types';
diff --git a/src/lib/clients/atcoder/atcoder_problems.test.ts b/src/lib/clients/atcoder/atcoder_problems.test.ts
index 8652495a7..9b78df8be 100644
--- a/src/lib/clients/atcoder/atcoder_problems.test.ts
+++ b/src/lib/clients/atcoder/atcoder_problems.test.ts
@@ -5,7 +5,7 @@ vi.mock('$lib/utils/time', () => ({
   delay: vi.fn().mockResolvedValue(undefined),
 }));
 
-import type { ContestsForImport } from '$lib/types/contest';
+import type { ContestsForImport } from '$lib/contests/types/contest';
 import type { TasksForImport } from '$lib/types/task';
 
 import { AtCoderProblemsApiClient } from '$lib/clients/atcoder/atcoder_problems';
diff --git a/src/lib/clients/atcoder/atcoder_problems.ts b/src/lib/clients/atcoder/atcoder_problems.ts
index b05b17a59..653509a57 100644
--- a/src/lib/clients/atcoder/atcoder_problems.ts
+++ b/src/lib/clients/atcoder/atcoder_problems.ts
@@ -1,6 +1,6 @@
 import { HttpRequestClient } from '$lib/clients/http_client';
 
-import type { ContestsForImport } from '$lib/types/contest';
+import type { ContestsForImport } from '$lib/contests/types/contest';
 import type { TasksForImport } from '$lib/types/task';
 
 import { ATCODER_PROBLEMS_API_BASE_URL } from '$lib/constants/urls';
diff --git a/src/lib/clients/cache_strategy.ts b/src/lib/clients/cache_strategy.ts
index 220343f74..3b9657536 100644
--- a/src/lib/clients/cache_strategy.ts
+++ b/src/lib/clients/cache_strategy.ts
@@ -1,6 +1,6 @@
 import { Cache } from '$lib/clients/cache';
 
-import type { ContestsForImport } from '$lib/types/contest';
+import type { ContestsForImport } from '$lib/contests/types/contest';
 import type { TasksForImport } from '$lib/types/task';
 
 export class ContestTaskCache {
diff --git a/src/lib/clients/contest_task_fetcher.ts b/src/lib/clients/contest_task_fetcher.ts
index 4fd25fbef..1310d669c 100644
--- a/src/lib/clients/contest_task_fetcher.ts
+++ b/src/lib/clients/contest_task_fetcher.ts
@@ -1,6 +1,6 @@
 import type { HttpRequestClient } from '$lib/clients/http_client';
 import type { ContestTaskCache } from '$lib/clients/cache_strategy';
-import type { ContestsForImport } from '$lib/types/contest';
+import type { ContestsForImport } from '$lib/contests/types/contest';
 import type { TasksForImport } from '$lib/types/task';
 
 type FetchContestsConfig<T> = {
diff --git a/src/lib/clients/http_client.ts b/src/lib/clients/http_client.ts
index beb9d0c3c..a01d7bdd0 100644
--- a/src/lib/clients/http_client.ts
+++ b/src/lib/clients/http_client.ts
@@ -1,4 +1,4 @@
-import type { ContestsForImport } from '$lib/types/contest';
+import type { ContestsForImport } from '$lib/contests/types/contest';
 import type { TasksForImport } from '$lib/types/task';
 import { delay } from '$lib/utils/time';
 
diff --git a/src/lib/clients/index.ts b/src/lib/clients/index.ts
index 1e4fa29f0..5b9c229d2 100644
--- a/src/lib/clients/index.ts
+++ b/src/lib/clients/index.ts
@@ -8,7 +8,7 @@ import {
   AojChallengesApiClient,
 } from '$lib/clients/aizu_online_judge/clients';
 
-import type { ContestsForImport } from '$lib/types/contest';
+import type { ContestsForImport } from '$lib/contests/types/contest';
 import type { TasksForImport } from '$lib/types/task';
 import type { ChallengeParams } from '$lib/clients/aizu_online_judge/types';
 
diff --git a/src/lib/components/SubmissionStatus/UpdatingModal.svelte b/src/lib/components/SubmissionStatus/UpdatingModal.svelte
index ed2fd4a12..74d94fe74 100644
--- a/src/lib/components/SubmissionStatus/UpdatingModal.svelte
+++ b/src/lib/components/SubmissionStatus/UpdatingModal.svelte
@@ -8,7 +8,7 @@
   import { submission_statuses } from '$lib/services/submission_status';
   import { errorMessageStore } from '$lib/stores/error_message';
 
-  import { getContestNameLabel } from '$lib/utils/contest';
+  import { getContestNameLabel } from '$lib/contests/utils/contest';
   import InputFieldWrapper from '$lib/components/InputFieldWrapper.svelte';
 
   interface Props {
diff --git a/src/lib/components/TagForm.svelte b/src/lib/components/TagForm.svelte
index ac007fe98..5561c6145 100644
--- a/src/lib/components/TagForm.svelte
+++ b/src/lib/components/TagForm.svelte
@@ -14,7 +14,7 @@
   import type { Task } from '$lib/types/task';
   import type { Tag } from '$lib/types/tag';
 
-  import { getContestNameLabel } from '$lib/utils/contest';
+  import { getContestNameLabel } from '$lib/contests/utils/contest';
   import { ATCODER_BASE_CONTEST_URL } from '$lib/constants/urls';
 
   interface Props {
diff --git a/src/lib/components/TaskForm.svelte b/src/lib/components/TaskForm.svelte
index 7badafcb1..1951a4746 100644
--- a/src/lib/components/TaskForm.svelte
+++ b/src/lib/components/TaskForm.svelte
@@ -10,7 +10,7 @@
     Label,
     Button,
   } from 'flowbite-svelte';
-  import { addContestNameToTaskIndex } from '$lib/utils/contest';
+  import { addContestNameToTaskIndex } from '$lib/contests/utils/contest';
   import { taskGradeValues, type Task } from '$lib/types/task';
   import { getTaskGradeLabel, removeTaskIndexFromTitle } from '$lib/utils/task';
 
diff --git a/src/lib/components/TaskList.svelte b/src/lib/components/TaskList.svelte
index f0fd84c4f..d74a8df7d 100644
--- a/src/lib/components/TaskList.svelte
+++ b/src/lib/components/TaskList.svelte
@@ -21,7 +21,7 @@
 
   import { getBackgroundColorFrom } from '$lib/services/submission_status';
 
-  import { addContestNameToTaskIndex } from '$lib/utils/contest';
+  import { addContestNameToTaskIndex } from '$lib/contests/utils/contest';
   import {
     countAcceptedTasks,
     countAllTasks,
diff --git a/src/lib/components/TaskListSorted.svelte b/src/lib/components/TaskListSorted.svelte
index 2264053b6..0c2a2f286 100644
--- a/src/lib/components/TaskListSorted.svelte
+++ b/src/lib/components/TaskListSorted.svelte
@@ -12,7 +12,7 @@
   } from 'flowbite-svelte';
   import type { TaskResults } from '$lib/types/task';
 
-  import { addContestNameToTaskIndex } from '$lib/utils/contest';
+  import { addContestNameToTaskIndex } from '$lib/contests/utils/contest';
   import { removeTaskIndexFromTitle } from '$lib/utils/task';
 
   interface Props {
diff --git a/src/test/lib/utils/test_cases/contest_name_and_task_index.ts b/src/lib/contests/fixtures/contest_name_and_task_index.ts
similarity index 99%
rename from src/test/lib/utils/test_cases/contest_name_and_task_index.ts
rename to src/lib/contests/fixtures/contest_name_and_task_index.ts
index df459adc5..23d75007e 100644
--- a/src/test/lib/utils/test_cases/contest_name_and_task_index.ts
+++ b/src/lib/contests/fixtures/contest_name_and_task_index.ts
@@ -1,4 +1,4 @@
-import { createTestCase, zip } from '../../common/test_helpers';
+import { createTestCase, zip } from '../../../test/lib/common/test_helpers';
 import {
   getPastContestLabel,
   getJoiContestLabel,
@@ -6,7 +6,7 @@ import {
   getAojContestLabel,
   PAST_TRANSLATIONS,
   AOJ_COURSES,
-} from '$lib/utils/contest';
+} from '$lib/contests/utils/contest';
 
 export type TestCaseForContestNameAndTaskIndex = {
   contestId: string;
diff --git a/src/test/lib/utils/test_cases/contest_name_labels.ts b/src/lib/contests/fixtures/contest_name_labels.ts
similarity index 99%
rename from src/test/lib/utils/test_cases/contest_name_labels.ts
rename to src/lib/contests/fixtures/contest_name_labels.ts
index 766b93ef6..fc7dad54f 100644
--- a/src/test/lib/utils/test_cases/contest_name_labels.ts
+++ b/src/lib/contests/fixtures/contest_name_labels.ts
@@ -1,4 +1,4 @@
-import { createTestCase } from '../../common/test_helpers';
+import { createTestCase } from '../../../test/lib/common/test_helpers';
 
 export type TestCaseForContestNameLabel = {
   contestId: string;
diff --git a/src/test/lib/utils/test_cases/contest_type.ts b/src/lib/contests/fixtures/contest_type.ts
similarity index 99%
rename from src/test/lib/utils/test_cases/contest_type.ts
rename to src/lib/contests/fixtures/contest_type.ts
index cb5118fd8..bb6a0de05 100644
--- a/src/test/lib/utils/test_cases/contest_type.ts
+++ b/src/lib/contests/fixtures/contest_type.ts
@@ -1,5 +1,5 @@
-import { createTestCase } from '../../common/test_helpers';
-import { ContestType } from '$lib/types/contest';
+import { createTestCase } from '../../../test/lib/common/test_helpers';
+import { ContestType } from '$lib/contests/types/contest';
 
 export type TestCaseForContestType = {
   contestId: string;
@@ -615,7 +615,7 @@ export const atCoderMainOfficialOnsite = [
 ];
 
 // See:
-// getPrefixForAojCourses() in src/lib/utils/contest.ts
+// getPrefixForAojCourses() in src/lib/contests/utils/contest.ts
 const aojCoursesData = [
   { name: 'AOJ Courses, ITP1', contestId: 'ITP1' },
   { name: 'AOJ Courses, ALDS1', contestId: 'ALDS1' },
diff --git a/src/lib/types/contest.ts b/src/lib/contests/types/contest.ts
similarity index 100%
rename from src/lib/types/contest.ts
rename to src/lib/contests/types/contest.ts
diff --git a/src/test/lib/utils/contest.test.ts b/src/lib/contests/utils/contest.test.ts
similarity index 97%
rename from src/test/lib/utils/contest.test.ts
rename to src/lib/contests/utils/contest.test.ts
index f22d1e5a2..eb1600212 100644
--- a/src/test/lib/utils/contest.test.ts
+++ b/src/lib/contests/utils/contest.test.ts
@@ -1,13 +1,13 @@
 import { expect } from 'vitest';
 
-import { ContestType } from '$lib/types/contest';
-import { runTests } from '../common/test_helpers';
-import * as TestCasesForContestType from './test_cases/contest_type';
-import { type TestCaseForContestType } from './test_cases/contest_type';
-import * as TestCasesForContestNameLabel from './test_cases/contest_name_labels';
-import { type TestCaseForContestNameLabel } from './test_cases/contest_name_labels';
-import * as TestCasesForContestNameAndTaskIndex from './test_cases/contest_name_and_task_index';
-import { type TestCaseForContestNameAndTaskIndex } from './test_cases/contest_name_and_task_index';
+import { ContestType } from '$lib/contests/types/contest';
+import { runTests } from '../../../test/lib/common/test_helpers';
+import * as TestCasesForContestType from '$lib/contests/fixtures/contest_type';
+import { type TestCaseForContestType } from '$lib/contests/fixtures/contest_type';
+import * as TestCasesForContestNameLabel from '$lib/contests/fixtures/contest_name_labels';
+import { type TestCaseForContestNameLabel } from '$lib/contests/fixtures/contest_name_labels';
+import * as TestCasesForContestNameAndTaskIndex from '$lib/contests/fixtures/contest_name_and_task_index';
+import { type TestCaseForContestNameAndTaskIndex } from '$lib/contests/fixtures/contest_name_and_task_index';
 import {
   classifyContest,
   getContestPriority,
@@ -15,7 +15,7 @@ import {
   getContestNameLabel,
   addContestNameToTaskIndex,
   getAtCoderUniversityContestLabel,
-} from '$lib/utils/contest';
+} from '$lib/contests/utils/contest';
 
 describe('Contest', () => {
   describe('classify contest', () => {
diff --git a/src/lib/utils/contest.ts b/src/lib/contests/utils/contest.ts
similarity index 99%
rename from src/lib/utils/contest.ts
rename to src/lib/contests/utils/contest.ts
index 3da6df5a2..5ec61cbef 100644
--- a/src/lib/utils/contest.ts
+++ b/src/lib/contests/utils/contest.ts
@@ -1,4 +1,8 @@
-import { ContestType, type ContestPrefix, type ContestLabelTranslations } from '$lib/types/contest';
+import {
+  ContestType,
+  type ContestPrefix,
+  type ContestLabelTranslations,
+} from '$lib/contests/types/contest';
 
 export const regexForJag = /^JAG(Prelim|Regional|Summer|Winter|Spring)\d{4}(-day\d+)?[A-Z]?$/;
 export const regexForAojUniversity = /^AOJ-[A-Z]+PC\d{4}/;
diff --git a/src/lib/services/tasks.ts b/src/lib/services/tasks.ts
index 81a8017e6..7b5e828db 100644
--- a/src/lib/services/tasks.ts
+++ b/src/lib/services/tasks.ts
@@ -3,7 +3,7 @@ import { default as db } from '$lib/server/database';
 
 import { getContestTaskPairs } from '$lib/services/contest_task_pairs';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import type { Task, Tasks, TaskGrade } from '$lib/types/task';
 import type {
   ContestTaskPair,
@@ -18,7 +18,7 @@ import {
 } from '$lib/server/tasks/cache';
 import { invalidateVoteCaches } from '$features/votes/server/cache';
 
-import { classifyContest } from '$lib/utils/contest';
+import { classifyContest } from '$lib/contests/utils/contest';
 import { createContestTaskPairKey } from '$lib/utils/contest_task_pair';
 
 // See:
diff --git a/src/lib/types/task.ts b/src/lib/types/task.ts
index d32dc6ea3..2ab3dbef9 100644
--- a/src/lib/types/task.ts
+++ b/src/lib/types/task.ts
@@ -1,6 +1,6 @@
 // Import original enum as type.
 import type { TaskGrade as TaskGradeOrigin } from '@prisma/client';
-import type { ContestType } from '$lib/types/contest';
+import type { ContestType } from '$lib/contests/types/contest';
 
 export interface Task {
   contest_type?: ContestType;
diff --git a/src/lib/utils/task.ts b/src/lib/utils/task.ts
index 3827cf94b..f67755165 100644
--- a/src/lib/utils/task.ts
+++ b/src/lib/utils/task.ts
@@ -1,4 +1,4 @@
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import { type TaskResult, type TaskResults, TaskGrade, type TaskGrades } from '$lib/types/task';
 import type { UrlGenerator, UrlGenerators } from '$lib/types/url';
 
@@ -10,7 +10,7 @@ import {
   getContestPriority,
   regexForAojUniversity,
   regexForJag,
-} from '$lib/utils/contest';
+} from '$lib/contests/utils/contest';
 
 // TODO: Codeforces、yukicoder、BOJなどに対応できるようにする
 /**
@@ -89,7 +89,7 @@ export function compareByContestIdAndTaskId(
   // 1. コンテスト種類別の優先度(昇順)
   //
   // See:
-  // contestTypePriorities in src/lib/utils/contest.ts
+  // contestTypePriorities in src/lib/contests/utils/contest.ts
   if (firstContestPriority !== secondContestPriority) {
     return firstContestPriority - secondContestPriority;
   }
diff --git a/src/lib/utils/task_filter.ts b/src/lib/utils/task_filter.ts
index ef08bd7ab..c011c4ef6 100644
--- a/src/lib/utils/task_filter.ts
+++ b/src/lib/utils/task_filter.ts
@@ -1,4 +1,4 @@
-import { getContestNameLabel } from '$lib/utils/contest';
+import { getContestNameLabel } from '$lib/contests/utils/contest';
 import { getTaskUrl } from '$lib/utils/task';
 
 type SearchableTask = {
diff --git a/src/routes/(admin)/tasks/+page.server.ts b/src/routes/(admin)/tasks/+page.server.ts
index fa4d081f2..4f070c7f0 100644
--- a/src/routes/(admin)/tasks/+page.server.ts
+++ b/src/routes/(admin)/tasks/+page.server.ts
@@ -1,6 +1,6 @@
 import { fail, type Actions } from '@sveltejs/kit';
 
-import type { Contests, ContestForImport, ContestsForImport } from '$lib/types/contest';
+import type { Contests, ContestForImport, ContestsForImport } from '$lib/contests/types/contest';
 import { type Task, type Tasks, type TaskForImport, type TasksForImport } from '$lib/types/task';
 
 import * as taskService from '$lib/services/tasks';
@@ -8,7 +8,7 @@ import { validateAdminAccess } from '$features/auth/services/admin_access';
 
 import { fetchContests, fetchTasks, isContestTaskImportSource } from '$lib/clients';
 
-import { classifyContest } from '$lib/utils/contest';
+import { classifyContest } from '$lib/contests/utils/contest';
 import { sha256 } from '$lib/utils/hash';
 
 import { BAD_REQUEST, INTERNAL_SERVER_ERROR } from '$lib/constants/http-response-status-codes';
diff --git a/src/routes/(admin)/tasks/+page.svelte b/src/routes/(admin)/tasks/+page.svelte
index 950adf07c..9df4e1ec4 100644
--- a/src/routes/(admin)/tasks/+page.svelte
+++ b/src/routes/(admin)/tasks/+page.svelte
@@ -5,7 +5,7 @@
 
   import { Select, Label, Button, PaginationNav } from 'flowbite-svelte';
 
-  import type { Contests } from '$lib/types/contest';
+  import type { Contests } from '$lib/contests/types/contest';
 
   import { importSourceEntries, type ContestTaskImportSource } from '$lib/clients';
 
diff --git a/src/routes/(admin)/tasks/_components/TaskTableForImport.svelte b/src/routes/(admin)/tasks/_components/TaskTableForImport.svelte
index 9df142602..0bc03db98 100644
--- a/src/routes/(admin)/tasks/_components/TaskTableForImport.svelte
+++ b/src/routes/(admin)/tasks/_components/TaskTableForImport.svelte
@@ -13,9 +13,9 @@
     Label,
   } from 'flowbite-svelte';
 
-  import type { Contests } from '$lib/types/contest';
+  import type { Contests } from '$lib/contests/types/contest';
   import type { ContestTaskImportSource } from '$lib/clients';
-  import { getContestNameLabel } from '$lib/utils/contest';
+  import { getContestNameLabel } from '$lib/contests/utils/contest';
   import { newline } from '$lib/utils/newline';
 
   interface Props {
diff --git a/src/routes/(admin)/tasks/_utils/contests.test.ts b/src/routes/(admin)/tasks/_utils/contests.test.ts
index ba497de31..aab04a36a 100644
--- a/src/routes/(admin)/tasks/_utils/contests.test.ts
+++ b/src/routes/(admin)/tasks/_utils/contests.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 import { filterContests } from './contests';
-import type { Contests } from '$lib/types/contest';
+import type { Contests } from '$lib/contests/types/contest';
 
 const contests: Contests = [
   {
diff --git a/src/routes/(admin)/tasks/_utils/contests.ts b/src/routes/(admin)/tasks/_utils/contests.ts
index 3486cc3cd..a02ed0f29 100644
--- a/src/routes/(admin)/tasks/_utils/contests.ts
+++ b/src/routes/(admin)/tasks/_utils/contests.ts
@@ -1,4 +1,4 @@
-import type { Contests } from '$lib/types/contest';
+import type { Contests } from '$lib/contests/types/contest';
 
 export function filterContests(contests: Contests, query: string): Contests {
   const hasNoQuery = !query || query.trim() === '';
diff --git a/src/routes/(admin)/tasks/grade/_components/TaskGradeTable.svelte b/src/routes/(admin)/tasks/grade/_components/TaskGradeTable.svelte
index adebfdfc8..3a55a777f 100644
--- a/src/routes/(admin)/tasks/grade/_components/TaskGradeTable.svelte
+++ b/src/routes/(admin)/tasks/grade/_components/TaskGradeTable.svelte
@@ -19,7 +19,7 @@
   import { taskGradeValues, TaskGrade } from '$lib/types/task';
   import type { TaskWithVoteInfo } from '$features/votes/services/vote_statistics';
 
-  import { addContestNameToTaskIndex } from '$lib/utils/contest';
+  import { addContestNameToTaskIndex } from '$lib/contests/utils/contest';
   import {
     getTaskGradeLabel,
     compareByContestIdAndTaskId,
diff --git a/src/routes/votes/+page.svelte b/src/routes/votes/+page.svelte
index 68af64e74..358d80f05 100644
--- a/src/routes/votes/+page.svelte
+++ b/src/routes/votes/+page.svelte
@@ -20,7 +20,7 @@
   import { TaskGrade } from '$lib/types/task';
   import { MIN_VOTES_FOR_PROVISIONAL_GRADE } from '$features/votes/constants/statistics';
 
-  import { getContestNameLabel } from '$lib/utils/contest';
+  import { getContestNameLabel } from '$lib/contests/utils/contest';
   import { getTaskUrl, compareByContestIdAndTaskId } from '$lib/utils/task';
   import { filterTasksBySearch } from '$lib/utils/task_filter';
   import { resolveDisplayGrade } from '$features/votes/utils/grade_options';
diff --git a/src/routes/workbooks/[slug]/+page.svelte b/src/routes/workbooks/[slug]/+page.svelte
index 9863ee84d..a490ebb13 100644
--- a/src/routes/workbooks/[slug]/+page.svelte
+++ b/src/routes/workbooks/[slug]/+page.svelte
@@ -20,7 +20,7 @@
   import CommentAndHint from '$features/workbooks/components/detail/CommentAndHint.svelte';
   import { getBackgroundColorFrom } from '$lib/services/submission_status';
 
-  import { addContestNameToTaskIndex } from '$lib/utils/contest';
+  import { addContestNameToTaskIndex } from '$lib/contests/utils/contest';
   import { getTaskUrl, removeTaskIndexFromTitle } from '$lib/utils/task';
 
   import type { TaskResult } from '$lib/types/task';
diff --git a/src/test/lib/services/fixtures/task_results.ts b/src/test/lib/services/fixtures/task_results.ts
index c4f63d289..cd17bee92 100644
--- a/src/test/lib/services/fixtures/task_results.ts
+++ b/src/test/lib/services/fixtures/task_results.ts
@@ -1,4 +1,4 @@
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import { TaskGrade } from '$lib/types/task';
 
 type MockedSubmissionStatus = {
diff --git a/src/test/lib/utils/task.test.ts b/src/test/lib/utils/task.test.ts
index f069db06a..8e8a3144e 100644
--- a/src/test/lib/utils/task.test.ts
+++ b/src/test/lib/utils/task.test.ts
@@ -13,7 +13,7 @@ import {
 } from './test_cases/task_results';
 import { taskResultsForTaskTableHeaderName } from './test_cases/task_table_header_name';
 
-import { ContestType } from '$lib/types/contest';
+import { ContestType } from '$lib/contests/types/contest';
 import { type TaskResult, type TaskResults } from '$lib/types/task';
 import type { WorkBookTaskBase } from '$features/workbooks/types/workbook';