diff --git a/docs/guides/how-to-add-contest-table-provider.md b/docs/guides/how-to-add-contest-table-provider.md
index 6fa6242f1..5eba16fa5 100644
--- a/docs/guides/how-to-add-contest-table-provider.md
+++ b/docs/guides/how-to-add-contest-table-provider.md
@@ -35,6 +35,12 @@
   - **パターン3（複合ソース型）**: ABS、ABC-Like など → 複数 contest_id を統一表示
   - 対応セクション: [実装パターン](#実装パターン)
 
+- [ ] **JOI の contest_id サフィックス変更の確認**
+  - JOI 本選は 2026 年より `joi{YYYY}ho` → `joi{YYYY}sf` にサフィックスが変更された
+  - `JOISemiFinalRoundProvider` の regex は `(ho|sf)` にマッチするよう対応済み
+  - `getJoiContestLabel()` は `sf` → `'セミファイナルステージ'` を返す
+  - テーブルの行ラベル (`getContestRoundLabel()`) は `sf` でも年のみ返す
+
 - [ ] **ガイドの実装例の確認**
   - 判定したパターンの実装例を確認してテンプレート理解
 
@@ -525,6 +531,7 @@ describe('CustomProvider with unique config', () => {
 - [#2785](https://github.com/AtCoder-NoviSteps/AtCoderNoviSteps/issues/2785) - MathAndAlgorithmProvider
 - [#2797](https://github.com/AtCoder-NoviSteps/AtCoderNoviSteps/issues/2797) - FPS24Provider
 - [#2920](https://github.com/AtCoder-NoviSteps/AtCoderNoviSteps/issues/2920)、[#3120](https://github.com/AtCoder-NoviSteps/AtCoderNoviSteps/issues/3120) - ACLPracticeProvider、ACLBeginnerProvider、ACLProvider
+- [#3152](https://github.com/AtCoder-NoviSteps/AtCoderNoviSteps/issues/3152) - JOISemiFinalRoundProvider（本選 → セミファイナルステージ への対応）
 
 ### 実装ファイル
 
@@ -534,4 +541,4 @@ describe('CustomProvider with unique config', () => {
 
 ---
 
-**最終更新**: 2026-02-14
+**最終更新**: 2026-02-22
diff --git a/prisma/tasks.ts b/prisma/tasks.ts
index 4478415ea..3fe94daac 100755
--- a/prisma/tasks.ts
+++ b/prisma/tasks.ts
@@ -7066,6 +7066,48 @@ export const tasks = [
     name: 'JOI 2006 予選 問題1',
     title: 'A. JOI 2006 予選 問題1',
   },
+  {
+    id: 'joi2026_semifinal_f',
+    contest_id: 'joi2026sf',
+    problem_index: 'F',
+    name: '奇妙な機械 (Strange Machine)',
+    title: 'F. 奇妙な機械 (Strange Machine)',
+  },
+  {
+    id: 'joi2026_semifinal_e',
+    contest_id: 'joi2026sf',
+    problem_index: 'E',
+    name: '新たな橋 (New Bridge)',
+    title: 'E. 新たな橋 (New Bridge)',
+  },
+  {
+    id: 'joi2026_semifinal_d',
+    contest_id: 'joi2026sf',
+    problem_index: 'D',
+    name: '川下り(River Rafting)',
+    title: 'D. 川下り(River Rafting)',
+  },
+  {
+    id: 'joi2026_semifinal_c',
+    contest_id: 'joi2026sf',
+    problem_index: 'C',
+    name: '衣服 (Clothes)',
+    title: 'C. 衣服 (Clothes)',
+  },
+  {
+    id: 'joi2026_semifinal_b',
+    contest_id: 'joi2026sf',
+    problem_index: 'B',
+    name: '宝石商 (Jeweler)',
+    title: 'B. 宝石商 (Jeweler)',
+  },
+  {
+    id: 'joi2026_semifinal_a',
+    contest_id: 'joi2026sf',
+    problem_index: 'A',
+    name: '座席 3 (Seats 3)',
+    title: 'A. 座席 3 (Seats 3)',
+  },
   {
     id: 'joi2025ho_e',
     contest_id: 'joi2025ho',
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 52d94514f..4b7013faa 100644
--- a/src/features/tasks/utils/contest-table/joi_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/joi_providers.test.ts
@@ -338,4 +338,46 @@ describe('JOISemiFinalRoundProvider', () => {
 
     expect(filtered).toEqual([]);
   });
+
+  test('expects to filter joi{YYYY}sf tasks (new format from 2026)', () => {
+    const provider = new JOISemiFinalRoundProvider(ContestType.JOI);
+    const mockJOITasks = [
+      { contest_id: 'joi2026sf', task_id: 'joi2026_semifinal_a' },
+      { contest_id: 'joi2026sf', task_id: 'joi2026_semifinal_b' },
+      { contest_id: 'joi2024ho', task_id: 'joi2024ho_a' },
+      { contest_id: 'joi2024yo2', task_id: 'joi2024yo2_a' },
+      { contest_id: 'joi2024yo1a', task_id: 'joi2024yo1a_a' },
+      { contest_id: 'abc123', task_id: 'abc123_a' },
+    ];
+
+    const filtered = provider.filter(mockJOITasks as any);
+
+    expect(filtered?.length).toBe(3);
+    expect(filtered?.some((task) => task.contest_id === 'joi2026sf')).toBe(true);
+    expect(filtered?.some((task) => task.contest_id === 'joi2024ho')).toBe(true);
+    expect(filtered?.every((task) => task.contest_id.startsWith('joi'))).toBe(true);
+  });
+
+  test('expects to get contest round label for joi{YYYY}sf', () => {
+    const provider = new JOISemiFinalRoundProvider(ContestType.JOI);
+
+    expect(provider.getContestRoundLabel('joi2026sf')).toBe('2026');
+  });
+
+  test('expects to generate correct table structure including joi{YYYY}sf', () => {
+    const provider = new JOISemiFinalRoundProvider(ContestType.JOI);
+    const mockJOITasks = [
+      { contest_id: 'joi2026sf', task_id: 'joi2026_semifinal_a', task_table_index: 'A' },
+      { contest_id: 'joi2026sf', task_id: 'joi2026_semifinal_b', task_table_index: 'B' },
+      { contest_id: 'joi2024ho', task_id: 'joi2024ho_a', task_table_index: 'A' },
+    ];
+
+    const table = provider.generateTable(mockJOITasks as any);
+
+    expect(table).toHaveProperty('joi2026sf');
+    expect(table).toHaveProperty('joi2024ho');
+    expect(table.joi2026sf).toHaveProperty('A');
+    expect(table.joi2026sf).toHaveProperty('B');
+    expect(table.joi2024ho).toHaveProperty('A');
+  });
 });
diff --git a/src/features/tasks/utils/contest-table/joi_providers.ts b/src/features/tasks/utils/contest-table/joi_providers.ts
index 986b73b37..9e78c1257 100644
--- a/src/features/tasks/utils/contest-table/joi_providers.ts
+++ b/src/features/tasks/utils/contest-table/joi_providers.ts
@@ -127,8 +127,10 @@ export class JOIQualRoundFrom2006To2019Provider extends ContestTableProviderBase
   }
 }
 
-const regexForJoiSemiFinalRound = /^(joi)(\d{4})(ho)$/i;
+const regexForJoiSemiFinalRound = /^(joi)(\d{4})(ho|sf)$/i;
 
+// Note: The JOI semi-final stage, which was renamed from the final round starting in 2026, is essentially the same as the final round in terms of its role in the competition.
+// Therefore, we can use the same provider for both the final round and the semi-final stage, as they share the same structure and purpose in the contest.
 export class JOISemiFinalRoundProvider extends ContestTableProviderBase {
   constructor(contestType: ContestType) {
     super(contestType, JOI_FINAL_ROUND_SECTIONS.semiFinal);
@@ -163,6 +165,6 @@ export class JOISemiFinalRoundProvider extends ContestTableProviderBase {
 
   getContestRoundLabel(contestId: string): string {
     const contestNameLabel = getContestNameLabel(contestId);
-    return contestNameLabel.replace('JOI 本選 ', '');
+    return contestNameLabel.replace('JOI 本選 ', '').replace('JOI セミファイナルステージ ', '');
   }
 }
diff --git a/src/lib/utils/contest.ts b/src/lib/utils/contest.ts
index f17a13eca..9df44b5b1 100644
--- a/src/lib/utils/contest.ts
+++ b/src/lib/utils/contest.ts
@@ -506,8 +506,9 @@ export function getPastContestLabel(
  * - "joisc2024" (matches)
  * - "joisp2022" (matches)
  * - "joi24yo3d" (does not match)
+ * - "joi2026sf" (matches)
  */
-const regexForJoi = /^(joi)(g|open)*(\d{4})*(yo|ho|sc|sp)*(\d{4})*(1|2)*(a|b|c)*/i;
+const regexForJoi = /^(joi)(g|open)*(\d{4})*(yo|ho|sc|sp|sf)*(\d{4})*(1|2)*(a|b|c)*/i;
 
 /**
  * Transforms a contest ID into a formatted contest label.
@@ -572,6 +573,8 @@ function addJoiDivisionNameIfNeeds(division: string, qual: string): string {
     }
   } else if (division === 'ho') {
     return '本選';
+  } else if (division === 'sf') {
+    return 'セミファイナルステージ';
   } else if (division === 'sc' || division === 'sp') {
     return '春合宿';
   }
diff --git a/src/test/lib/utils/test_cases/contest_name_and_task_index.ts b/src/test/lib/utils/test_cases/contest_name_and_task_index.ts
index 5f11f3005..a07e6da9f 100644
--- a/src/test/lib/utils/test_cases/contest_name_and_task_index.ts
+++ b/src/test/lib/utils/test_cases/contest_name_and_task_index.ts
@@ -212,6 +212,10 @@ const JOI_TEST_DATA = {
     contestId: 'joi2024ho',
     tasks: ['A', 'B', 'E'],
   },
+  joi2026sf: {
+    contestId: 'joi2026sf',
+    tasks: ['A', 'B', 'F'],
+  },
   joisc2007: {
     contestId: 'joisc2007',
     tasks: ['anagra', 'buildi', 'salt', 'score'],