diff --git a/CHANGELOG.md b/CHANGELOG.md
index e72777d23..ab09b9a76 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -37,6 +37,7 @@
 
 ### Client
 - Enhance: 二要素認証のバックアップコード一覧をテキストファイルでダウンロード可能に
+- Enhance: 動画再生時のデフォルトボリュームを30%に
 - Fix: リアクションしたユーザ一覧のUIが稀に左上に残ってしまう不具合を修正
 
 ### Server
diff --git a/packages/frontend/src/components/MkMediaBanner.vue b/packages/frontend/src/components/MkMediaBanner.vue
index 10b2ac9ec..69da1a746 100644
--- a/packages/frontend/src/components/MkMediaBanner.vue
+++ b/packages/frontend/src/components/MkMediaBanner.vue
@@ -17,7 +17,6 @@ SPDX-License-Identifier: AGPL-3.0-only
 			:title="media.name"
 			controls
 			preload="metadata"
-			@volumechange="volumechange"
 		/>
 	</div>
 	<a
@@ -33,7 +32,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 </template>
 
 <script lang="ts" setup>
-import { onMounted } from 'vue';
+import { onMounted, shallowRef, watch } from 'vue';
 import * as Misskey from 'misskey-js';
 import { soundConfigStore } from '@/scripts/sound.js';
 import { i18n } from '@/i18n.js';
@@ -43,15 +42,13 @@ const props = withDefaults(defineProps<{
 }>(), {
 });
 
-const audioEl = $shallowRef<HTMLAudioElement | null>();
+const audioEl = shallowRef<HTMLAudioElement>();
 let hide = $ref(true);
 
-function volumechange() {
-	if (audioEl) soundConfigStore.set('mediaVolume', audioEl.volume);
-}
-
-onMounted(() => {
-	if (audioEl) audioEl.volume = soundConfigStore.state.mediaVolume;
+watch(audioEl, () => {
+	if (audioEl.value) {
+		audioEl.value.volume = 0.3;
+	}
 });
 </script>
 
diff --git a/packages/frontend/src/components/MkMediaVideo.vue b/packages/frontend/src/components/MkMediaVideo.vue
index 751b5f757..43c64b4c8 100644
--- a/packages/frontend/src/components/MkMediaVideo.vue
+++ b/packages/frontend/src/components/MkMediaVideo.vue
@@ -14,6 +14,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 </div>
 <div v-else :class="[$style.visible, (video.isSensitive && defaultStore.state.highlightSensitiveMedia) && $style.sensitiveContainer]">
 	<video
+		ref="videoEl"
 		:class="$style.video"
 		:poster="video.thumbnailUrl"
 		:title="video.comment"
@@ -31,7 +32,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 </template>
 
 <script lang="ts" setup>
-import { ref } from 'vue';
+import { ref, shallowRef, watch } from 'vue';
 import * as Misskey from 'misskey-js';
 import bytes from '@/filters/bytes.js';
 import { defaultStore } from '@/store.js';
@@ -42,6 +43,14 @@ const props = defineProps<{
 }>();
 
 const hide = ref((defaultStore.state.nsfw === 'force' || defaultStore.state.enableDataSaverMode) ? true : (props.video.isSensitive && defaultStore.state.nsfw !== 'ignore'));
+
+const videoEl = shallowRef<HTMLVideoElement>();
+
+watch(videoEl, () => {
+	if (videoEl.value) {
+		videoEl.value.volume = 0.3;
+	}
+});
 </script>
 
 <style lang="scss" module>
diff --git a/packages/frontend/src/scripts/sound.ts b/packages/frontend/src/scripts/sound.ts
index c7b532861..1ef075818 100644
--- a/packages/frontend/src/scripts/sound.ts
+++ b/packages/frontend/src/scripts/sound.ts
@@ -7,10 +7,6 @@ import { markRaw } from 'vue';
 import { Storage } from '@/pizzax.js';
 
 export const soundConfigStore = markRaw(new Storage('sound', {
-	mediaVolume: {
-		where: 'device',
-		default: 0.5,
-	},
 	sound_masterVolume: {
 		where: 'device',
 		default: 0.3,