diff --git a/packages/frontend/src/pages/mahjong/room.game.vue b/packages/frontend/src/pages/mahjong/room.game.vue
index 61b1280d33..20cec2dd14 100644
--- a/packages/frontend/src/pages/mahjong/room.game.vue
+++ b/packages/frontend/src/pages/mahjong/room.game.vue
@@ -307,7 +307,7 @@ const $i = ensureSignin();
 
 const props = defineProps<{
 	room: Misskey.entities.MahjongRoomDetailed;
-	connection?: Misskey.ChannelConnection | null;
+	connection?: Misskey.ChannelConnection<Misskey.Channels['mahjongRoom']> | null;
 }>();
 
 const room = ref<Misskey.entities.MahjongRoomDetailed>(deepClone(props.room));
diff --git a/packages/frontend/src/pages/mahjong/room.setting.vue b/packages/frontend/src/pages/mahjong/room.setting.vue
index 63f7d72e65..29504013f6 100644
--- a/packages/frontend/src/pages/mahjong/room.setting.vue
+++ b/packages/frontend/src/pages/mahjong/room.setting.vue
@@ -69,7 +69,7 @@ const router = useRouter();
 
 const props = defineProps<{
 	room: Misskey.entities.MahjongRoomDetailed;
-	connection: Misskey.ChannelConnection;
+	connection: Misskey.ChannelConnection<Misskey.Channels['mahjongRoom']>;
 }>();
 
 const room = ref<Misskey.entities.MahjongRoomDetailed>(deepClone(props.room));
diff --git a/packages/frontend/src/pages/mahjong/room.vue b/packages/frontend/src/pages/mahjong/room.vue
index 16bcda1726..b4962d2a53 100644
--- a/packages/frontend/src/pages/mahjong/room.vue
+++ b/packages/frontend/src/pages/mahjong/room.vue
@@ -32,7 +32,7 @@ const props = defineProps<{
 }>();
 
 const room = shallowRef<Misskey.entities.MahjongRoomDetailed | null>(null);
-const connection = shallowRef<Misskey.ChannelConnection | null>(null);
+const connection = shallowRef<Misskey.ChannelConnection<Misskey.Channels['mahjongRoom']> | null>(null);
 const shareWhenStart = ref(false);
 
 watch(() => props.roomId, () => {
diff --git a/packages/misskey-js/src/streaming.types.ts b/packages/misskey-js/src/streaming.types.ts
index 10204fb2c9..102ad24b24 100644
--- a/packages/misskey-js/src/streaming.types.ts
+++ b/packages/misskey-js/src/streaming.types.ts
@@ -4,6 +4,7 @@ import {
 	ChatMessageLite,
 	DriveFile,
 	DriveFolder,
+	MahjongRoomDetailed,
 	Note,
 	Notification,
 	Signin,
@@ -32,6 +33,8 @@ type ReversiUpdateSettings<K extends ReversiUpdateKey> = {
 	value: ReversiGameDetailed[K];
 };
 
+type MmjHouse = 'e' | 's' | 'w' | 'n';
+
 export type Channels = {
 	main: {
 		params: null;
@@ -277,6 +280,106 @@ export type Channels = {
 			};
 		};
 	};
+	mahjongRoom: {
+		params: {
+			roomId: string;
+		};
+		events: {
+			joined: (payload: {
+				index: number;
+				user: UserLite | null;
+			}) => void;
+			changeReadyStates: (payload: {
+				user1: boolean;
+				user2: boolean;
+				user3: boolean;
+				user4: boolean;
+			}) => void;
+			started: (payload: { room: MahjongRoomDetailed }) => void;
+			nextKyoku: (payload: { room: MahjongRoomDetailed }) => void;
+			tsumo: (payload: {
+				house: MmjHouse;
+				tile: number;
+			}) => void;
+			dahai: (payload: {
+				house: MmjHouse;
+				tile: number;
+				riichi: boolean;
+			}) => void;
+			dahaiAndTsumo: (payload: {
+				dahaiHouse: MmjHouse;
+				dahaiTile: number;
+				tsumoTile: number;
+				riichi: boolean;
+			}) => void;
+			ponned: (payload: {
+				caller: MmjHouse;
+				callee: MmjHouse;
+				tiles: readonly [number, number, number];
+			}) => void;
+			kanned: (payload: {
+				caller: MmjHouse;
+				callee: MmjHouse;
+				tiles: readonly [number, number, number, number];
+				rinsyan: number;
+			}) => void;
+			ciied: (payload: {
+				caller: MmjHouse;
+				callee: MmjHouse;
+				tiles: readonly [number, number, number];
+			}) => void;
+			ronned: (payload: {
+				callers: MmjHouse[];
+				callee: MmjHouse;
+				handTiles: Record<MmjHouse, number[]>;
+			}) => void;
+			ryuukyoku: (payload: unknown) => void;
+			ankanned: (payload: {
+				house: MmjHouse;
+				tiles: readonly [number, number, number, number];
+				rinsyan: number;
+			}) => void;
+			kakanned: (payload: {
+				house: MmjHouse;
+				tiles: readonly [number, number, number, number];
+				rinsyan: number;
+				from: MmjHouse;
+			}) => void;
+			tsumoHora: (payload: {
+				house: MmjHouse;
+				handTiles: number[];
+				tsumoTile: number;
+			}) => void;
+		};
+		receives: {
+			ready: boolean;
+			updateSettings: {
+				key: string;
+				body: unknown;
+			};
+			addAi: Record<string, never>;
+			confirmNextKyoku: Record<string, never>;
+			dahai: {
+				tile: number;
+				riichi?: boolean;
+			};
+			tsumoHora: Record<string, never>;
+			ronHora: Record<string, never>;
+			pon: Record<string, never>;
+			cii: {
+				pattern: string;
+			};
+			kan: Record<string, never>;
+			ankan: {
+				tile: number;
+			};
+			kakan: {
+				tile: number;
+			};
+			nop: Record<string, never>;
+			claimTimeIsUp: Record<string, never>;
+		};
+	};
 };
 
 export type NoteUpdatedEvent = { id: Note['id'] } & ({