diff --git a/locales/index.d.ts b/locales/index.d.ts
index 9ab72b3a5a..d7b1c3b9b0 100644
--- a/locales/index.d.ts
+++ b/locales/index.d.ts
@@ -5472,6 +5472,14 @@ export interface Locale extends ILocale {
          * ルームを削除
          */
         "deleteRoom": string;
+        /**
+         * このサーバー、またはこのアカウントでチャットは有効化されていません。
+         */
+        "chatNotAvailableForThisAccountOrServer": string;
+        /**
+         * 相手のアカウントでチャット機能が使えない状態になっています。
+         */
+        "chatNotAvailableInOtherAccount": string;
         /**
          * このユーザーとのチャットを開始できません
          */
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index 7a2beb7a87..7ab6c24d82 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -1365,6 +1365,8 @@ _chat:
   newline: "改行"
   muteThisRoom: "このルームをミュート"
   deleteRoom: "ルームを削除"
+  chatNotAvailableForThisAccountOrServer: "このサーバー、またはこのアカウントでチャットは有効化されていません。"
+  chatNotAvailableInOtherAccount: "相手のアカウントでチャット機能が使えない状態になっています。"
   cannotChatWithTheUser: "このユーザーとのチャットを開始できません"
   cannotChatWithTheUser_description: "チャットが使えない状態になっているか、相手がチャットを開放していません。"
   chatWithThisUser: "チャットする"
diff --git a/packages/backend/src/core/entities/UserEntityService.ts b/packages/backend/src/core/entities/UserEntityService.ts
index 92a684dc1a..ad8052711c 100644
--- a/packages/backend/src/core/entities/UserEntityService.ts
+++ b/packages/backend/src/core/entities/UserEntityService.ts
@@ -557,6 +557,7 @@ export class UserEntityService implements OnModuleInit {
 				followersVisibility: profile!.followersVisibility,
 				followingVisibility: profile!.followingVisibility,
 				chatScope: user.chatScope,
+				canChat: this.roleService.getUserPolicies(user.id).then(r => r.canChat),
 				roles: this.roleService.getUserRoles(user.id).then(roles => roles.filter(role => role.isPublic).sort((a, b) => b.displayOrder - a.displayOrder).map(role => ({
 					id: role.id,
 					name: role.name,
diff --git a/packages/backend/src/models/json-schema/user.ts b/packages/backend/src/models/json-schema/user.ts
index 0094f25e34..e475296702 100644
--- a/packages/backend/src/models/json-schema/user.ts
+++ b/packages/backend/src/models/json-schema/user.ts
@@ -363,6 +363,10 @@ export const packedUserDetailedNotMeOnlySchema = {
 			nullable: false, optional: false,
 			enum: ['everyone', 'following', 'followers', 'mutual', 'none'],
 		},
+		canChat: {
+			type: 'boolean',
+			nullable: false, optional: false,
+		},
 		roles: {
 			type: 'array',
 			nullable: false, optional: false,
diff --git a/packages/frontend/src/pages/chat/home.home.vue b/packages/frontend/src/pages/chat/home.home.vue
index 0affef6333..007e9fc1f4 100644
--- a/packages/frontend/src/pages/chat/home.home.vue
+++ b/packages/frontend/src/pages/chat/home.home.vue
@@ -5,7 +5,9 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <template>
 <div class="_gaps">
-	<MkButton primary gradate rounded :class="$style.start" @click="start"><i class="ti ti-plus"></i> {{ i18n.ts.startChat }}</MkButton>
+	<MkButton v-if="$i.policies.canChat" primary gradate rounded :class="$style.start" @click="start"><i class="ti ti-plus"></i> {{ i18n.ts.startChat }}</MkButton>
+
+	<MkInfo v-else>{{ i18n.ts._chat.chatNotAvailableForThisAccountOrServer }}</MkInfo>
 
 	<MkAd :prefer="['horizontal', 'horizontal-big']"/>
 
@@ -78,6 +80,7 @@ import * as os from '@/os.js';
 import { updateCurrentAccountPartial } from '@/accounts.js';
 import MkInput from '@/components/MkInput.vue';
 import MkFoldableSection from '@/components/MkFoldableSection.vue';
+import MkInfo from '@/components/MkInfo.vue';
 
 const $i = ensureSignin();
 
diff --git a/packages/frontend/src/pages/chat/room.vue b/packages/frontend/src/pages/chat/room.vue
index 5938fd2688..ec92a1dce1 100644
--- a/packages/frontend/src/pages/chat/room.vue
+++ b/packages/frontend/src/pages/chat/room.vue
@@ -41,6 +41,12 @@ SPDX-License-Identifier: AGPL-3.0-only
 				<XMessage v-for="message in messages.toReversed()" :key="message.id" :message="message"/>
 			</TransitionGroup>
 		</div>
+
+		<div v-if="user && (!user.canChat || user.host !== null)">
+			<MkInfo warn>{{ i18n.ts._chat.chatNotAvailableInOtherAccount }}</MkInfo>
+		</div>
+
+		<MkInfo v-if="!$i.policies.canChat" warn>{{ i18n.ts._chat.chatNotAvailableForThisAccountOrServer }}</MkInfo>
 	</MkSpacer>
 
 	<MkSpacer v-else-if="tab === 'search'" :contentMax="700">
@@ -93,6 +99,7 @@ import { prefer } from '@/preferences.js';
 import MkButton from '@/components/MkButton.vue';
 import { useRouter } from '@/router.js';
 import { useMutationObserver } from '@/use/use-mutation-observer.js';
+import MkInfo from '@/components/MkInfo.vue';
 
 const $i = ensureSignin();
 const router = useRouter();
diff --git a/packages/frontend/src/utility/get-user-menu.ts b/packages/frontend/src/utility/get-user-menu.ts
index 37c88c9665..10429c8ff1 100644
--- a/packages/frontend/src/utility/get-user-menu.ts
+++ b/packages/frontend/src/utility/get-user-menu.ts
@@ -362,12 +362,18 @@ export function getUserMenu(user: Misskey.entities.UserDetailed, router: Router
 				const canonical = user.host === null ? `@${user.username}` : `@${user.username}@${user.host}`;
 				os.post({ specified: user, initialText: `${canonical} ` });
 			},
-		}, {
-			type: 'link',
-			icon: 'ti ti-messages',
-			text: i18n.ts._chat.chatWithThisUser,
-			to: `/chat/user/${user.id}`,
-		}, { type: 'divider' }, {
+		});
+
+		if ($i.policies.canChat && user.canChat && user.host == null) {
+			menuItems.push({
+				type: 'link',
+				icon: 'ti ti-messages',
+				text: i18n.ts._chat.chatWithThisUser,
+				to: `/chat/user/${user.id}`,
+			});
+		}
+
+		menuItems.push({ type: 'divider' }, {
 			icon: user.isMuted ? 'ti ti-eye' : 'ti ti-eye-off',
 			text: user.isMuted ? i18n.ts.unmute : i18n.ts.mute,
 			action: toggleMute,
diff --git a/packages/misskey-js/src/autogen/types.ts b/packages/misskey-js/src/autogen/types.ts
index c91fedf2fa..57c4824424 100644
--- a/packages/misskey-js/src/autogen/types.ts
+++ b/packages/misskey-js/src/autogen/types.ts
@@ -4057,6 +4057,7 @@ export type components = {
       followersVisibility: 'public' | 'followers' | 'private';
       /** @enum {string} */
       chatScope: 'everyone' | 'following' | 'followers' | 'mutual' | 'none';
+      canChat: boolean;
       roles: components['schemas']['RoleLite'][];
       followedMessage?: string | null;
       memo: string | null;