diff --git a/apps/server/src/infra/sync/sync.module.ts b/apps/server/src/infra/sync/sync.module.ts
index 40e02c83966..02bff2032ab 100644
--- a/apps/server/src/infra/sync/sync.module.ts
+++ b/apps/server/src/infra/sync/sync.module.ts
@@ -10,6 +10,7 @@ import { LoggerModule } from '@src/core/logger';
 import { ProvisioningModule } from '@src/modules/provisioning';
 import { SyncConsole } from './console/sync.console';
 import { SyncService } from './service/sync.service';
+import { TspLegacyMigrationService } from './tsp/tsp-legacy-migration.service';
 import { TspOauthDataMapper } from './tsp/tsp-oauth-data.mapper';
 import { TspSyncService } from './tsp/tsp-sync.service';
 import { TspSyncStrategy } from './tsp/tsp-sync.strategy';
@@ -28,7 +29,7 @@ import { SyncUc } from './uc/sync.uc';
 		SyncUc,
 		SyncService,
 		...((Configuration.get('FEATURE_TSP_SYNC_ENABLED') as boolean)
-			? [TspSyncStrategy, TspSyncService, TspOauthDataMapper]
+			? [TspSyncStrategy, TspSyncService, TspOauthDataMapper, TspLegacyMigrationService]
 			: []),
 	],
 	exports: [SyncConsole],
diff --git a/apps/server/src/infra/sync/tsp/tsp-legacy-migration.service.ts b/apps/server/src/infra/sync/tsp/tsp-legacy-migration.service.ts
new file mode 100644
index 00000000000..eab60f1c3e3
--- /dev/null
+++ b/apps/server/src/infra/sync/tsp/tsp-legacy-migration.service.ts
@@ -0,0 +1,64 @@
+import { EntityManager, ObjectId } from '@mikro-orm/mongodb';
+import { Injectable } from '@nestjs/common';
+import { SchoolProperties } from '@shared/domain/entity';
+import { EntityId } from '@shared/domain/types';
+import { Logger } from '@src/core/logger';
+
+@Injectable()
+export class TspLegacyMigrationService {
+	constructor(private readonly em: EntityManager, private readonly logger: Logger) {
+		logger.setContext(TspLegacyMigrationService.name);
+	}
+
+	public async migrateLegacyData(newSystemId: EntityId): Promise<void> {
+		console.log('starting legacy migration');
+		const legacySystemId = await this.findLegacySystemId();
+
+		if (!legacySystemId) {
+			console.log('No legacy system found');
+			return;
+		}
+
+		const schools = await this.em.find<
+			SchoolProperties & {
+				sourceOptions: {
+					schoolIdentifier: number;
+				};
+			}
+		>('schools', {
+			systems: [legacySystemId],
+			source: 'tsp',
+		});
+
+		const schoolIds = schools.map((school) => school.sourceOptions.schoolIdentifier);
+
+		console.log('Number of schools', schoolIds);
+
+		const promises = schoolIds.map((oldId) =>
+			this.em.nativeUpdate(
+				'schools',
+				{
+					systems: [legacySystemId],
+					source: 'tsp',
+				},
+				{
+					$unset: { sourceOptions: '' },
+					ldapSchoolIdentifier: oldId,
+					systems: [new ObjectId(newSystemId)],
+				}
+			)
+		);
+
+		const res = await Promise.allSettled(promises);
+		const success = res.map((r) => r.status === 'fulfilled').length;
+		console.log(`Migrated ${schoolIds.length} legacy schools to new system. ${success} succeeded.`);
+	}
+
+	private async findLegacySystemId() {
+		const tspLegacySystem = await this.em.getCollection('systems').findOne({
+			type: 'tsp-school',
+		});
+
+		return tspLegacySystem?._id;
+	}
+}
diff --git a/apps/server/src/infra/sync/tsp/tsp-sync.strategy.ts b/apps/server/src/infra/sync/tsp/tsp-sync.strategy.ts
index b7273d7cfdc..c889c69252c 100644
--- a/apps/server/src/infra/sync/tsp/tsp-sync.strategy.ts
+++ b/apps/server/src/infra/sync/tsp/tsp-sync.strategy.ts
@@ -16,6 +16,7 @@ import { TspSyncingUsersLoggable } from './loggable/tsp-syncing-users.loggable';
 import { TspOauthDataMapper } from './tsp-oauth-data.mapper';
 import { TspSyncConfig } from './tsp-sync.config';
 import { TspSyncService } from './tsp-sync.service';
+import { TspLegacyMigrationService } from './tsp-legacy-migration.service';
 
 @Injectable()
 export class TspSyncStrategy extends SyncStrategy {
@@ -31,6 +32,7 @@ export class TspSyncStrategy extends SyncStrategy {
 		private readonly logger: Logger,
 		private readonly tspSyncService: TspSyncService,
 		private readonly tspOauthDataMapper: TspOauthDataMapper,
+		private readonly tspLegacyMigrationService: TspLegacyMigrationService,
 		configService: ConfigService<TspSyncConfig, true>,
 		private readonly provisioningService: ProvisioningService
 	) {
@@ -51,6 +53,8 @@ export class TspSyncStrategy extends SyncStrategy {
 	public async sync(): Promise<void> {
 		const system = await this.tspSyncService.findTspSystemOrFail();
 
+		await this.tspLegacyMigrationService.migrateLegacyData(system.id);
+
 		await this.syncSchools(system);
 
 		const schools = await this.tspSyncService.findSchoolsForSystem(system);