diff --git a/packages/backend/migration/1672704017999-remove-lastCommunicatedAt.js b/packages/backend/migration/1672704017999-remove-lastCommunicatedAt.js
new file mode 100644
index 000000000..38a676985
--- /dev/null
+++ b/packages/backend/migration/1672704017999-remove-lastCommunicatedAt.js
@@ -0,0 +1,11 @@
+export class removeLastCommunicatedAt1672704017999 {
+    name = 'removeLastCommunicatedAt1672704017999'
+
+    async up(queryRunner) {
+        await queryRunner.query(`ALTER TABLE "instance" DROP COLUMN "lastCommunicatedAt"`);
+    }
+
+    async down(queryRunner) {
+        await queryRunner.query(`ALTER TABLE "instance" ADD "lastCommunicatedAt" TIMESTAMP WITH TIME ZONE NOT NULL`);
+    }
+}
diff --git a/packages/backend/src/core/FederatedInstanceService.ts b/packages/backend/src/core/FederatedInstanceService.ts
index 97745a116..48e77caae 100644
--- a/packages/backend/src/core/FederatedInstanceService.ts
+++ b/packages/backend/src/core/FederatedInstanceService.ts
@@ -35,7 +35,6 @@ export class FederatedInstanceService {
 				id: this.idService.genId(),
 				host,
 				caughtAt: new Date(),
-				lastCommunicatedAt: new Date(),
 			}).then(x => this.instancesRepository.findOneByOrFail(x.identifiers[0]));
 	
 			this.cache.set(host, i);
diff --git a/packages/backend/src/core/chart/charts/federation.ts b/packages/backend/src/core/chart/charts/federation.ts
index d9234e802..b8012809f 100644
--- a/packages/backend/src/core/chart/charts/federation.ts
+++ b/packages/backend/src/core/chart/charts/federation.ts
@@ -86,7 +86,7 @@ export default class FederationChart extends Chart<typeof schema> {
 				.where(`instance.host IN (${ subInstancesQuery.getQuery() })`)
 				.andWhere(meta.blockedHosts.length === 0 ? '1=1' : 'instance.host NOT IN (:...blocked)', { blocked: meta.blockedHosts })
 				.andWhere('instance.isSuspended = false')
-				.andWhere('instance.lastCommunicatedAt > :gt', { gt: new Date(Date.now() - (1000 * 60 * 60 * 24 * 30)) })
+				.andWhere('instance.isNotResponding = false')
 				.getRawOne()
 				.then(x => parseInt(x.count, 10)),
 			this.instancesRepository.createQueryBuilder('instance')
@@ -94,7 +94,7 @@ export default class FederationChart extends Chart<typeof schema> {
 				.where(`instance.host IN (${ pubInstancesQuery.getQuery() })`)
 				.andWhere(meta.blockedHosts.length === 0 ? '1=1' : 'instance.host NOT IN (:...blocked)', { blocked: meta.blockedHosts })
 				.andWhere('instance.isSuspended = false')
-				.andWhere('instance.lastCommunicatedAt > :gt', { gt: new Date(Date.now() - (1000 * 60 * 60 * 24 * 30)) })
+				.andWhere('instance.isNotResponding = false')
 				.getRawOne()
 				.then(x => parseInt(x.count, 10)),
 		]);
diff --git a/packages/backend/src/core/entities/InstanceEntityService.ts b/packages/backend/src/core/entities/InstanceEntityService.ts
index 7742608b0..81d02bb33 100644
--- a/packages/backend/src/core/entities/InstanceEntityService.ts
+++ b/packages/backend/src/core/entities/InstanceEntityService.ts
@@ -33,7 +33,6 @@ export class InstanceEntityService {
 			notesCount: instance.notesCount,
 			followingCount: instance.followingCount,
 			followersCount: instance.followersCount,
-			lastCommunicatedAt: instance.lastCommunicatedAt.toISOString(),
 			isNotResponding: instance.isNotResponding,
 			isSuspended: instance.isSuspended,
 			isBlocked: meta.blockedHosts.includes(instance.host),
diff --git a/packages/backend/src/models/entities/Instance.ts b/packages/backend/src/models/entities/Instance.ts
index e4e9835ce..40d964dec 100644
--- a/packages/backend/src/models/entities/Instance.ts
+++ b/packages/backend/src/models/entities/Instance.ts
@@ -75,12 +75,6 @@ export class Instance {
 	})
 	public latestRequestReceivedAt: Date | null;
 
-	/**
-	 * このインスタンスと最後にやり取りした日時
-	 */
-	@Column('timestamp with time zone')
-	public lastCommunicatedAt: Date;
-
 	/**
 	 * このインスタンスと不通かどうか
 	 */
diff --git a/packages/backend/src/models/schema/federation-instance.ts b/packages/backend/src/models/schema/federation-instance.ts
index 739548103..f3f93f309 100644
--- a/packages/backend/src/models/schema/federation-instance.ts
+++ b/packages/backend/src/models/schema/federation-instance.ts
@@ -32,11 +32,6 @@ export const packedFederationInstanceSchema = {
 			type: 'number',
 			optional: false, nullable: false,
 		},
-		lastCommunicatedAt: {
-			type: 'string',
-			optional: false, nullable: false,
-			format: 'date-time',
-		},
 		isNotResponding: {
 			type: 'boolean',
 			optional: false, nullable: false,
diff --git a/packages/backend/src/queue/processors/DeliverProcessorService.ts b/packages/backend/src/queue/processors/DeliverProcessorService.ts
index 0e7426038..571b9e904 100644
--- a/packages/backend/src/queue/processors/DeliverProcessorService.ts
+++ b/packages/backend/src/queue/processors/DeliverProcessorService.ts
@@ -86,7 +86,6 @@ export class DeliverProcessorService {
 			this.federatedInstanceService.registerOrFetchInstanceDoc(host).then(i => {
 				this.instancesRepository.update(i.id, {
 					latestStatus: 200,
-					lastCommunicatedAt: new Date(),
 					isNotResponding: false,
 				});
 
diff --git a/packages/backend/src/queue/processors/InboxProcessorService.ts b/packages/backend/src/queue/processors/InboxProcessorService.ts
index c032122ca..56058638c 100644
--- a/packages/backend/src/queue/processors/InboxProcessorService.ts
+++ b/packages/backend/src/queue/processors/InboxProcessorService.ts
@@ -179,7 +179,6 @@ export class InboxProcessorService {
 		this.federatedInstanceService.registerOrFetchInstanceDoc(authUser.user.host).then(i => {
 			this.instancesRepository.update(i.id, {
 				latestRequestReceivedAt: new Date(),
-				lastCommunicatedAt: new Date(),
 				isNotResponding: false,
 			});
 
diff --git a/packages/backend/src/server/api/endpoints/federation/instances.ts b/packages/backend/src/server/api/endpoints/federation/instances.ts
index 81276a7ab..6672434fb 100644
--- a/packages/backend/src/server/api/endpoints/federation/instances.ts
+++ b/packages/backend/src/server/api/endpoints/federation/instances.ts
@@ -64,8 +64,6 @@ export default class extends Endpoint<typeof meta, typeof paramDef> {
 				case '-followers': query.orderBy('instance.followersCount', 'ASC'); break;
 				case '+caughtAt': query.orderBy('instance.caughtAt', 'DESC'); break;
 				case '-caughtAt': query.orderBy('instance.caughtAt', 'ASC'); break;
-				case '+lastCommunicatedAt': query.orderBy('instance.lastCommunicatedAt', 'DESC'); break;
-				case '-lastCommunicatedAt': query.orderBy('instance.lastCommunicatedAt', 'ASC'); break;
 
 				default: query.orderBy('instance.id', 'DESC'); break;
 			}
diff --git a/packages/frontend/src/pages/about.federation.vue b/packages/frontend/src/pages/about.federation.vue
index 2b20f383d..1709f06a1 100644
--- a/packages/frontend/src/pages/about.federation.vue
+++ b/packages/frontend/src/pages/about.federation.vue
@@ -30,15 +30,13 @@
 				<option value="-followers">{{ i18n.ts.followers }} ({{ i18n.ts.ascendingOrder }})</option>
 				<option value="+caughtAt">{{ i18n.ts.registeredAt }} ({{ i18n.ts.descendingOrder }})</option>
 				<option value="-caughtAt">{{ i18n.ts.registeredAt }} ({{ i18n.ts.ascendingOrder }})</option>
-				<option value="+lastCommunicatedAt">{{ i18n.ts.lastCommunication }} ({{ i18n.ts.descendingOrder }})</option>
-				<option value="-lastCommunicatedAt">{{ i18n.ts.lastCommunication }} ({{ i18n.ts.ascendingOrder }})</option>
 			</MkSelect>
 		</FormSplit>
 	</div>
 
 	<MkPagination v-slot="{items}" ref="instances" :key="host + state" :pagination="pagination">
 		<div class="dqokceoi">
-			<MkA v-for="instance in items" :key="instance.id" v-tooltip.mfm="`Last communicated: ${dateString(instance.lastCommunicatedAt)}\nStatus: ${getStatus(instance)}`" class="instance" :to="`/instance-info/${instance.host}`">
+			<MkA v-for="instance in items" :key="instance.id" v-tooltip.mfm="`Status: ${getStatus(instance)}`" class="instance" :to="`/instance-info/${instance.host}`">
 				<MkInstanceCardMini :instance="instance"/>
 			</MkA>
 		</div>
diff --git a/packages/frontend/src/pages/admin/overview.instances.vue b/packages/frontend/src/pages/admin/overview.instances.vue
index ae10017aa..15dbdc463 100644
--- a/packages/frontend/src/pages/admin/overview.instances.vue
+++ b/packages/frontend/src/pages/admin/overview.instances.vue
@@ -22,7 +22,7 @@ const fetching = ref(true);
 
 const fetch = async () => {
 	const fetchedInstances = await os.api('federation/instances', {
-		sort: '+lastCommunicatedAt',
+		sort: '+latestRequestReceivedAt',
 		limit: 6,
 	});
 	instances.value = fetchedInstances;
diff --git a/packages/frontend/src/pages/admin/overview.vue b/packages/frontend/src/pages/admin/overview.vue
index d656e5520..5fdfa5f26 100644
--- a/packages/frontend/src/pages/admin/overview.vue
+++ b/packages/frontend/src/pages/admin/overview.vue
@@ -153,7 +153,7 @@ onMounted(async () => {
 	});
 
 	os.api('federation/instances', {
-		sort: '+lastCommunicatedAt',
+		sort: '+latestRequestReceivedAt',
 		limit: 25,
 	}).then(res => {
 		activeInstances = res;
diff --git a/packages/frontend/src/ui/_common_/statusbar-federation.vue b/packages/frontend/src/ui/_common_/statusbar-federation.vue
index 7c3de32ac..70d683d75 100644
--- a/packages/frontend/src/ui/_common_/statusbar-federation.vue
+++ b/packages/frontend/src/ui/_common_/statusbar-federation.vue
@@ -44,7 +44,7 @@ let key = $ref(0);
 
 const tick = () => {
 	os.api('federation/instances', {
-		sort: '+lastCommunicatedAt',
+		sort: '+latestRequestReceivedAt',
 		limit: 30,
 	}).then(res => {
 		instances.value = res;
diff --git a/packages/frontend/src/widgets/federation.vue b/packages/frontend/src/widgets/federation.vue
index 221972bc6..a701ca567 100644
--- a/packages/frontend/src/widgets/federation.vue
+++ b/packages/frontend/src/widgets/federation.vue
@@ -58,7 +58,7 @@ const fetching = ref(true);
 
 const fetch = async () => {
 	const fetchedInstances = await os.api('federation/instances', {
-		sort: '+lastCommunicatedAt',
+		sort: '+latestRequestReceivedAt',
 		limit: 5,
 	});
 	const fetchedCharts = await Promise.all(fetchedInstances.map(i => os.apiGet('charts/instance', { host: i.host, limit: 16, span: 'hour' })));
diff --git a/packages/frontend/src/widgets/instance-cloud.vue b/packages/frontend/src/widgets/instance-cloud.vue
index 496561699..6d522ddbe 100644
--- a/packages/frontend/src/widgets/instance-cloud.vue
+++ b/packages/frontend/src/widgets/instance-cloud.vue
@@ -54,7 +54,7 @@ function onInstanceClick(i) {
 
 useInterval(() => {
 	os.api('federation/instances', {
-		sort: '+lastCommunicatedAt',
+		sort: '+latestRequestReceivedAt',
 		limit: 25,
 	}).then(res => {
 		activeInstances = res;