diff --git a/CHANGELOG.md b/CHANGELOG.md
index b3a60736ab..7f62cd6ac0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ v2025.12.0で行われた「configの`trustProxy`のデフォルト値を`false`
 
 ### Client
 - Enhance: デッキのUI説明を追加
+- Enhance: 設定がブラウザによって消去されないようにするオプションを追加
 - Fix: バージョン表記のないPlayが正しく動作しない問題を修正  
   バージョン表記のないものは v0.x 系として実行されます。v1.x 系で動作させたい場合は必ずバージョン表記を含めてください。
 - Fix: デッキUIでメニュー位置を下にしているとプロファイル削除ボタンが表示されないのを修正  
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index 643095bc52..1eea745e0c 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -1557,6 +1557,9 @@ _settings:
   showPageTabBarBottom: "ページのタブバーを下部に表示"
   emojiPaletteBanner: "絵文字ピッカーに固定表示するプリセットをパレットとして登録したり、ピッカーの表示方法をカスタマイズしたりできます。"
   enableAnimatedImages: "アニメーション画像を有効にする"
+  settingsPersistence_title: "設定の永続化"
+  settingsPersistence_description1: "設定の永続化を有効にすると、設定情報が失われるのを防止できます。"
+  settingsPersistence_description2: "環境によっては有効化できない場合があります。"
 
   _chat:
     showSenderName: "送信者の名前を表示"
diff --git a/packages/frontend/src/pages/settings/index.vue b/packages/frontend/src/pages/settings/index.vue
index 250c1735be..39c32d347f 100644
--- a/packages/frontend/src/pages/settings/index.vue
+++ b/packages/frontend/src/pages/settings/index.vue
@@ -11,6 +11,11 @@ SPDX-License-Identifier: AGPL-3.0-only
 				<div v-if="!narrow || currentPage?.route.name == null" class="nav">
 					<div class="_gaps_s">
 						<MkInfo v-if="emailNotConfigured" warn class="info">{{ i18n.ts.emailNotConfiguredWarning }} <MkA to="/settings/email" class="_link">{{ i18n.ts.configure }}</MkA></MkInfo>
+						<MkInfo v-if="!storagePersisted && store.r.showStoragePersistenceSuggestion.value" class="info">
+							<div>{{ i18n.ts._settings.settingsPersistence_description1 }}</div>
+							<div>{{ i18n.ts._settings.settingsPersistence_description2 }}</div>
+							<div><button class="_textButton" @click="enableStoragePersistence">{{ i18n.ts.enable }}</button> | <button class="_textButton" @click="skipStoragePersistence">{{ i18n.ts.skip }}</button></div>
+						</MkInfo>
 						<MkInfo v-if="!store.r.enablePreferencesAutoCloudBackup.value && store.r.showPreferencesAutoCloudBackupSuggestion.value" class="info">
 							<div>{{ i18n.ts._preferencesBackup.autoPreferencesBackupIsNotEnabledForThisDevice }}</div>
 							<div><button class="_textButton" @click="enableAutoBackup">{{ i18n.ts.enable }}</button> | <button class="_textButton" @click="skipAutoBackup">{{ i18n.ts.skip }}</button></div>
@@ -46,6 +51,7 @@ import { enableAutoBackup, getPreferencesProfileMenu } from '@/preferences/utili
 import { store } from '@/store.js';
 import { signout } from '@/signout.js';
 import { genSearchIndexes } from '@/utility/inapp-search.js';
+import { enableStoragePersistence, storagePersisted, skipStoragePersistence } from '@/utility/storage.js';
 
 const searchIndex = await import('search-index:settings').then(({ searchIndexes }) => genSearchIndexes(searchIndexes));
 
diff --git a/packages/frontend/src/pages/settings/other.vue b/packages/frontend/src/pages/settings/other.vue
index e6ee3bfb1c..d4097bde94 100644
--- a/packages/frontend/src/pages/settings/other.vue
+++ b/packages/frontend/src/pages/settings/other.vue
@@ -142,6 +142,8 @@ SPDX-License-Identifier: AGPL-3.0-only
 			<hr>
 		</template>
 
+		<MkButton v-if="!storagePersisted" @click="enableStoragePersistence">{{ i18n.ts._settings.settingsPersistence_title }}</MkButton>
+
 		<MkButton @click="forceCloudBackup">{{ i18n.ts._preferencesBackup.forceBackup }}</MkButton>
 
 		<FormSlot>
@@ -163,7 +165,7 @@ import MkKeyValue from '@/components/MkKeyValue.vue';
 import MkButton from '@/components/MkButton.vue';
 import FormSlot from '@/components/form/slot.vue';
 import * as os from '@/os.js';
-import { misskeyApi } from '@/utility/misskey-api.js';
+import { enableStoragePersistence, storagePersisted, skipStoragePersistence } from '@/utility/storage.js';
 import { ensureSignin } from '@/i.js';
 import { i18n } from '@/i18n.js';
 import { definePage } from '@/page.js';
diff --git a/packages/frontend/src/store.ts b/packages/frontend/src/store.ts
index 073fbba0fb..fb9349c42f 100644
--- a/packages/frontend/src/store.ts
+++ b/packages/frontend/src/store.ts
@@ -118,6 +118,10 @@ export const store = markRaw(new Pizzax('base', {
 		where: 'device',
 		default: true,
 	},
+	showStoragePersistenceSuggestion: {
+		where: 'device',
+		default: true,
+	},
 
 	//#region TODO: そのうち消す (preferに移行済み)
 	defaultWithReplies: {
diff --git a/packages/frontend/src/utility/storage.ts b/packages/frontend/src/utility/storage.ts
new file mode 100644
index 0000000000..9df3a251e6
--- /dev/null
+++ b/packages/frontend/src/utility/storage.ts
@@ -0,0 +1,34 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { computed, ref, shallowRef, watch, defineAsyncComponent } from 'vue';
+import * as os from '@/os.js';
+import { store } from '@/store.js';
+import { i18n } from '@/i18n.js';
+
+export const storagePersisted = ref(await navigator.storage.persisted());
+
+export async function enableStoragePersistence() {
+	try {
+		const persisted = await navigator.storage.persist();
+		if (persisted) {
+			storagePersisted.value = true;
+		} else {
+			os.alert({
+				type: 'error',
+				text: i18n.ts.somethingHappened,
+			});
+		}
+	}	catch (err) {
+		os.alert({
+			type: 'error',
+			text: i18n.ts.somethingHappened,
+		});
+	}
+}
+
+export function skipStoragePersistence() {
+	store.set('showStoragePersistenceSuggestion', false);
+}
diff --git a/packages/i18n/src/autogen/locale.ts b/packages/i18n/src/autogen/locale.ts
index 55833b0cfc..96a728da63 100644
--- a/packages/i18n/src/autogen/locale.ts
+++ b/packages/i18n/src/autogen/locale.ts
@@ -6193,6 +6193,18 @@ export interface Locale extends ILocale {
          * アニメーション画像を有効にする
          */
         "enableAnimatedImages": string;
+        /**
+         * 設定の永続化
+         */
+        "settingsPersistence_title": string;
+        /**
+         * 設定の永続化を有効にすると、設定情報が失われるのを防止できます。
+         */
+        "settingsPersistence_description1": string;
+        /**
+         * 環境によっては有効化できない場合があります。
+         */
+        "settingsPersistence_description2": string;
         "_chat": {
             /**
              * 送信者の名前を表示