diff --git a/ApiCore-Backend/src/apiaries/apiaries.controller.ts b/ApiCore-Backend/src/apiaries/apiaries.controller.ts
index 5cb38af..866dece 100644
--- a/ApiCore-Backend/src/apiaries/apiaries.controller.ts
+++ b/ApiCore-Backend/src/apiaries/apiaries.controller.ts
@@ -59,4 +59,10 @@ export class ApiariesController {
   deactivate(@Param('id') id: string, @CurrentUser() actor: AuthenticatedUser) {
     return this.apiariesService.deactivate(id, actor.id);
   }
+
+  @Roles(Role.ADMIN, Role.BEEKEEPER)
+  @Post(':id/reactivate')
+  reactivate(@Param('id') id: string, @CurrentUser() actor: AuthenticatedUser) {
+    return this.apiariesService.reactivate(id, actor.id);
+  }
 }
diff --git a/ApiCore-Backend/src/apiaries/apiaries.service.spec.ts b/ApiCore-Backend/src/apiaries/apiaries.service.spec.ts
index 20fcd2c..9467667 100644
--- a/ApiCore-Backend/src/apiaries/apiaries.service.spec.ts
+++ b/ApiCore-Backend/src/apiaries/apiaries.service.spec.ts
@@ -1,4 +1,4 @@
-import { NotFoundException } from '@nestjs/common';
+import { ConflictException, NotFoundException } from '@nestjs/common';
 import { ApiariesService } from './apiaries.service';
 import { PrismaService } from '../prisma/prisma.service';
 import { AuditLogService } from '../audit/audit-log.service';
@@ -75,4 +75,35 @@ describe('ApiariesService', () => {
       expect.objectContaining({ entityType: 'Apiary', action: 'DEACTIVATE' }),
     );
   });
+
+  it('reactivate throws ConflictException when already active', async () => {
+    prisma.apiary.findUnique.mockResolvedValue(existingApiary);
+    await expect(
+      service.reactivate('apiary-1', 'user-1'),
+    ).rejects.toBeInstanceOf(ConflictException);
+  });
+
+  it('reactivate sets status to ACTIVE and clears deactivatedAt', async () => {
+    prisma.apiary.findUnique.mockResolvedValue({
+      ...existingApiary,
+      status: 'INACTIVE',
+      deactivatedAt: new Date(),
+    });
+    prisma.apiary.update.mockResolvedValue({
+      ...existingApiary,
+      status: 'ACTIVE',
+      deactivatedAt: null,
+    });
+
+    const result = await service.reactivate('apiary-1', 'user-1');
+
+    expect(result.status).toBe('ACTIVE');
+    expect(prisma.apiary.update).toHaveBeenCalledWith({
+      where: { id: 'apiary-1' },
+      data: { status: 'ACTIVE', deactivatedAt: null },
+    });
+    expect(auditLog.record).toHaveBeenCalledWith(
+      expect.objectContaining({ entityType: 'Apiary', action: 'UPDATE' }),
+    );
+  });
 });
diff --git a/ApiCore-Backend/src/apiaries/apiaries.service.ts b/ApiCore-Backend/src/apiaries/apiaries.service.ts
index 8d9d9c1..8a957fa 100644
--- a/ApiCore-Backend/src/apiaries/apiaries.service.ts
+++ b/ApiCore-Backend/src/apiaries/apiaries.service.ts
@@ -1,4 +1,8 @@
-import { Injectable, NotFoundException } from '@nestjs/common';
+import {
+  ConflictException,
+  Injectable,
+  NotFoundException,
+} from '@nestjs/common';
 import { PrismaService } from '../prisma/prisma.service';
 import { AuditLogService } from '../audit/audit-log.service';
 import { Apiary, ApiaryStatus } from '../../generated/prisma';
@@ -86,4 +90,24 @@ export class ApiariesService {
     });
     return apiary;
   }
+
+  async reactivate(id: string, actingUserId: string): Promise<Apiary> {
+    const before = await this.findById(id);
+    if (before.status === 'ACTIVE') {
+      throw new ConflictException('Apiary is already active');
+    }
+    const apiary = await this.prisma.apiary.update({
+      where: { id },
+      data: { status: 'ACTIVE', deactivatedAt: null },
+    });
+    await this.auditLog.record({
+      entityType: 'Apiary',
+      entityId: id,
+      action: 'UPDATE',
+      userId: actingUserId,
+      beforeData: before,
+      afterData: apiary,
+    });
+    return apiary;
+  }
 }
diff --git a/ApiCore-Backend/src/colonies/colonies.controller.ts b/ApiCore-Backend/src/colonies/colonies.controller.ts
index 8e2a560..0f53197 100644
--- a/ApiCore-Backend/src/colonies/colonies.controller.ts
+++ b/ApiCore-Backend/src/colonies/colonies.controller.ts
@@ -97,4 +97,10 @@ export class ColoniesController {
   dissolve(@Param('id') id: string, @CurrentUser() actor: AuthenticatedUser) {
     return this.coloniesService.dissolve(id, actor.id);
   }
+
+  @Roles(Role.ADMIN, Role.BEEKEEPER)
+  @Post(':id/reactivate')
+  reactivate(@Param('id') id: string, @CurrentUser() actor: AuthenticatedUser) {
+    return this.coloniesService.reactivate(id, actor.id);
+  }
 }
diff --git a/ApiCore-Backend/src/colonies/colonies.service.spec.ts b/ApiCore-Backend/src/colonies/colonies.service.spec.ts
index 8d6277b..fbcf78a 100644
--- a/ApiCore-Backend/src/colonies/colonies.service.spec.ts
+++ b/ApiCore-Backend/src/colonies/colonies.service.spec.ts
@@ -170,4 +170,35 @@ describe('ColoniesService', () => {
       expect.objectContaining({ action: 'DEACTIVATE' }),
     );
   });
+
+  it('reactivate throws ConflictException when already active', async () => {
+    prisma.colony.findUnique.mockResolvedValue(parentColony);
+    await expect(
+      service.reactivate('colony-1', 'user-1'),
+    ).rejects.toBeInstanceOf(ConflictException);
+  });
+
+  it('reactivate sets status ACTIVE and clears deactivatedAt', async () => {
+    prisma.colony.findUnique.mockResolvedValue({
+      ...parentColony,
+      status: 'DISSOLVED',
+      deactivatedAt: new Date(),
+    });
+    prisma.colony.update.mockResolvedValue({
+      ...parentColony,
+      status: 'ACTIVE',
+      deactivatedAt: null,
+    });
+
+    const result = await service.reactivate('colony-1', 'user-1');
+
+    expect(result.status).toBe('ACTIVE');
+    expect(prisma.colony.update).toHaveBeenCalledWith({
+      where: { id: 'colony-1' },
+      data: { status: 'ACTIVE', deactivatedAt: null },
+    });
+    expect(auditLog.record).toHaveBeenCalledWith(
+      expect.objectContaining({ action: 'UPDATE' }),
+    );
+  });
 });
diff --git a/ApiCore-Backend/src/colonies/colonies.service.ts b/ApiCore-Backend/src/colonies/colonies.service.ts
index 85a257e..08234fd 100644
--- a/ApiCore-Backend/src/colonies/colonies.service.ts
+++ b/ApiCore-Backend/src/colonies/colonies.service.ts
@@ -212,6 +212,26 @@ export class ColoniesService {
     return colony;
   }
 
+  async reactivate(id: string, actingUserId: string): Promise<Colony> {
+    const before = await this.findById(id);
+    if (before.status === 'ACTIVE') {
+      throw new ConflictException('Colony is already active');
+    }
+    const colony = await this.prisma.colony.update({
+      where: { id },
+      data: { status: 'ACTIVE', deactivatedAt: null },
+    });
+    await this.auditLog.record({
+      entityType: 'Colony',
+      entityId: id,
+      action: 'UPDATE',
+      userId: actingUserId,
+      beforeData: before,
+      afterData: colony,
+    });
+    return colony;
+  }
+
   async getHistory(id: string) {
     await this.findById(id);
     const [apiaryHistory, queenHistory, lineageAsSource, lineageAsResult] =
diff --git a/ApiCore-Backend/test/apiaries.e2e-spec.ts b/ApiCore-Backend/test/apiaries.e2e-spec.ts
index b3b7aae..9cb1eb5 100644
--- a/ApiCore-Backend/test/apiaries.e2e-spec.ts
+++ b/ApiCore-Backend/test/apiaries.e2e-spec.ts
@@ -115,5 +115,16 @@ describe('Apiaries (e2e)', () => {
       .set('Authorization', `Bearer ${beekeeperToken}`)
       .expect(201);
     expect((deactivated.body as ApiaryBody).status).toBe('INACTIVE');
+
+    const reactivated = await request(app.getHttpServer())
+      .post(`/api/v1/apiaries/${apiaryId}/reactivate`)
+      .set('Authorization', `Bearer ${beekeeperToken}`)
+      .expect(201);
+    expect((reactivated.body as ApiaryBody).status).toBe('ACTIVE');
+
+    await request(app.getHttpServer())
+      .post(`/api/v1/apiaries/${apiaryId}/reactivate`)
+      .set('Authorization', `Bearer ${beekeeperToken}`)
+      .expect(409);
   });
 });
diff --git a/ApiCore-Backend/test/colonies.e2e-spec.ts b/ApiCore-Backend/test/colonies.e2e-spec.ts
index d4beda6..9208781 100644
--- a/ApiCore-Backend/test/colonies.e2e-spec.ts
+++ b/ApiCore-Backend/test/colonies.e2e-spec.ts
@@ -195,4 +195,17 @@ describe('Colonies (e2e)', () => {
       .send({ apiaryId: apiaryAId })
       .expect(409);
   });
+
+  it('reactivates a dissolved colony, and rejects reactivating an already-active one', async () => {
+    const response = await request(app.getHttpServer())
+      .post(`/api/v1/colonies/${colonyId}/reactivate`)
+      .set('Authorization', `Bearer ${beekeeperToken}`)
+      .expect(201);
+    expect((response.body as ColonyBody).status).toBe('ACTIVE');
+
+    await request(app.getHttpServer())
+      .post(`/api/v1/colonies/${colonyId}/reactivate`)
+      .set('Authorization', `Bearer ${beekeeperToken}`)
+      .expect(409);
+  });
 });