diff --git a/app/Jobs/DatabaseBackupJob.php b/app/Jobs/DatabaseBackupJob.php
index bd31ab0c3..64e900b49 100644
--- a/app/Jobs/DatabaseBackupJob.php
+++ b/app/Jobs/DatabaseBackupJob.php
@@ -668,12 +668,14 @@ class DatabaseBackupJob implements ShouldBeEncrypted, ShouldQueue
     private function upload_to_s3(): void
     {
         if (is_null($this->s3)) {
+            $previousS3StorageId = $this->backup->s3_storage_id;
+
             $this->backup->update([
                 'save_s3' => false,
                 's3_storage_id' => null,
             ]);
 
-            throw new \Exception('S3 storage configuration is missing or has been deleted (S3 storage ID: '.($this->backup->s3_storage_id ?? 'null').'). S3 backup has been disabled for this schedule.');
+            throw new \Exception('S3 storage configuration is missing or has been deleted (S3 storage ID: '.($previousS3StorageId ?? 'null').'). S3 backup has been disabled for this schedule.');
         }
 
         try {
diff --git a/app/Livewire/Project/Database/BackupEdit.php b/app/Livewire/Project/Database/BackupEdit.php
index a18022882..ef106a65f 100644
--- a/app/Livewire/Project/Database/BackupEdit.php
+++ b/app/Livewire/Project/Database/BackupEdit.php
@@ -3,6 +3,7 @@
 namespace App\Livewire\Project\Database;
 
 use App\Models\ScheduledDatabaseBackup;
+use App\Models\ServiceDatabase;
 use Exception;
 use Illuminate\Foundation\Auth\Access\AuthorizesRequests;
 use Livewire\Attributes\Locked;
@@ -144,7 +145,7 @@ class BackupEdit extends Component
 
         try {
             $server = null;
-            if ($this->backup->database instanceof \App\Models\ServiceDatabase) {
+            if ($this->backup->database instanceof ServiceDatabase) {
                 $server = $this->backup->database->service->destination->server;
             } elseif ($this->backup->database->destination && $this->backup->database->destination->server) {
                 $server = $this->backup->database->destination->server;
@@ -170,7 +171,7 @@ class BackupEdit extends Component
 
             $this->backup->delete();
 
-            if ($this->backup->database->getMorphClass() === \App\Models\ServiceDatabase::class) {
+            if ($this->backup->database->getMorphClass() === ServiceDatabase::class) {
                 $serviceDatabase = $this->backup->database;
 
                 return redirect()->route('project.service.database.backups', [
@@ -182,7 +183,7 @@ class BackupEdit extends Component
             } else {
                 return redirect()->route('project.database.backup.index', $this->parameters);
             }
-        } catch (\Exception $e) {
+        } catch (Exception $e) {
             $this->dispatch('error', 'Failed to delete backup: '.$e->getMessage());
 
             return handleError($e, $this);
@@ -207,6 +208,13 @@ class BackupEdit extends Component
             $this->backup->s3_storage_id = null;
         }
 
+        // S3 backup cannot be enabled without a valid S3 storage owned by the team
+        $availableS3Ids = collect($this->s3s)->pluck('id');
+        if ($this->backup->save_s3 && ! $availableS3Ids->contains($this->backup->s3_storage_id)) {
+            $this->backup->save_s3 = $this->saveS3 = false;
+            $this->backup->s3_storage_id = $this->s3StorageId = null;
+        }
+
         // Validate that disable_local_backup can only be true when S3 backup is enabled
         if ($this->backup->disable_local_backup && ! $this->backup->save_s3) {
             $this->backup->disable_local_backup = $this->disableLocalBackup = false;
@@ -214,7 +222,7 @@ class BackupEdit extends Component
 
         $isValid = validate_cron_expression($this->backup->frequency);
         if (! $isValid) {
-            throw new \Exception('Invalid Cron / Human expression');
+            throw new Exception('Invalid Cron / Human expression');
         }
         $this->validate();
     }
diff --git a/app/Livewire/Project/Database/CreateScheduledBackup.php b/app/Livewire/Project/Database/CreateScheduledBackup.php
index 7f807afe2..bb8b8b9c7 100644
--- a/app/Livewire/Project/Database/CreateScheduledBackup.php
+++ b/app/Livewire/Project/Database/CreateScheduledBackup.php
@@ -3,6 +3,7 @@
 namespace App\Livewire\Project\Database;
 
 use App\Models\ScheduledDatabaseBackup;
+use App\Models\ServiceDatabase;
 use Illuminate\Foundation\Auth\Access\AuthorizesRequests;
 use Illuminate\Support\Collection;
 use Livewire\Attributes\Locked;
@@ -48,6 +49,14 @@ class CreateScheduledBackup extends Component
 
             $this->validate();
 
+            if ($this->saveToS3) {
+                if (is_null($this->s3StorageId) || ! $this->definedS3s->contains('id', $this->s3StorageId)) {
+                    $this->dispatch('error', 'Please select a valid S3 storage to enable S3 backups.');
+
+                    return;
+                }
+            }
+
             $isValid = validate_cron_expression($this->frequency);
             if (! $isValid) {
                 $this->dispatch('error', 'Invalid Cron / Human expression.');
@@ -74,7 +83,7 @@ class CreateScheduledBackup extends Component
             }
 
             $databaseBackup = ScheduledDatabaseBackup::create($payload);
-            if ($this->database->getMorphClass() === \App\Models\ServiceDatabase::class) {
+            if ($this->database->getMorphClass() === ServiceDatabase::class) {
                 $this->dispatch('refreshScheduledBackups', $databaseBackup->id);
             } else {
                 $this->dispatch('refreshScheduledBackups');
diff --git a/app/Models/S3Storage.php b/app/Models/S3Storage.php
index 3f6ee51cc..fca74170d 100644
--- a/app/Models/S3Storage.php
+++ b/app/Models/S3Storage.php
@@ -15,6 +15,7 @@ class S3Storage extends BaseModel
     use HasFactory, HasSafeStringAttribute;
 
     protected $fillable = [
+        'team_id',
         'name',
         'description',
         'region',
diff --git a/app/Models/ScheduledDatabaseBackupExecution.php b/app/Models/ScheduledDatabaseBackupExecution.php
index 51ad46de9..1d5f5f9ce 100644
--- a/app/Models/ScheduledDatabaseBackupExecution.php
+++ b/app/Models/ScheduledDatabaseBackupExecution.php
@@ -23,6 +23,7 @@ class ScheduledDatabaseBackupExecution extends BaseModel
     protected function casts(): array
     {
         return [
+            'size' => 'integer',
             's3_uploaded' => 'boolean',
             'local_storage_deleted' => 'boolean',
             's3_storage_deleted' => 'boolean',
diff --git a/tests/Feature/BackupEditValidationTest.php b/tests/Feature/BackupEditValidationTest.php
new file mode 100644
index 000000000..8894f0f69
--- /dev/null
+++ b/tests/Feature/BackupEditValidationTest.php
@@ -0,0 +1,85 @@
+<?php
+
+use App\Livewire\Project\Database\BackupEdit;
+use App\Models\Environment;
+use App\Models\InstanceSettings;
+use App\Models\Project;
+use App\Models\ScheduledDatabaseBackup;
+use App\Models\Server;
+use App\Models\StandaloneDocker;
+use App\Models\StandalonePostgresql;
+use App\Models\Team;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Livewire\Livewire;
+
+uses(RefreshDatabase::class);
+
+function createBackupForEditValidationTest(Team $team, array $overrides = []): ScheduledDatabaseBackup
+{
+    $server = Server::factory()->create(['team_id' => $team->id]);
+    $destination = StandaloneDocker::where('server_id', $server->id)->firstOrFail();
+    $project = Project::factory()->create(['team_id' => $team->id]);
+    $environment = Environment::factory()->create(['project_id' => $project->id]);
+
+    $database = StandalonePostgresql::create([
+        'name' => 'pg-backup-edit-validation',
+        'image' => 'postgres:16-alpine',
+        'postgres_user' => 'postgres',
+        'postgres_password' => 'password',
+        'postgres_db' => 'postgres',
+        'environment_id' => $environment->id,
+        'destination_id' => $destination->id,
+        'destination_type' => $destination->getMorphClass(),
+    ]);
+
+    return ScheduledDatabaseBackup::create(array_merge([
+        'frequency' => '0 0 * * *',
+        'save_s3' => true,
+        's3_storage_id' => null,
+        'database_type' => $database->getMorphClass(),
+        'database_id' => $database->id,
+        'team_id' => $team->id,
+    ], $overrides));
+}
+
+beforeEach(function () {
+    if (InstanceSettings::find(0) === null) {
+        $settings = new InstanceSettings;
+        $settings->id = 0;
+        $settings->save();
+    }
+
+    $this->team = Team::factory()->create();
+    $this->user = User::factory()->create();
+    $this->user->teams()->attach($this->team, ['role' => 'owner']);
+    $this->actingAs($this->user);
+    session(['currentTeam' => $this->team]);
+});
+
+it('disables S3 backup when saved without a selected S3 storage', function () {
+    $backup = createBackupForEditValidationTest($this->team);
+
+    Livewire::test(BackupEdit::class, ['backup' => $backup->fresh(), 's3s' => $this->team->s3s])
+        ->call('submit')
+        ->assertDispatched('success');
+
+    $backup->refresh();
+    expect($backup->save_s3)->toBeFalsy();
+    expect($backup->s3_storage_id)->toBeNull();
+});
+
+it('cascades to disabling local backup deletion when S3 is force-disabled', function () {
+    $backup = createBackupForEditValidationTest($this->team, [
+        'disable_local_backup' => true,
+    ]);
+
+    Livewire::test(BackupEdit::class, ['backup' => $backup->fresh(), 's3s' => $this->team->s3s])
+        ->call('submit')
+        ->assertDispatched('success');
+
+    $backup->refresh();
+    expect($backup->save_s3)->toBeFalsy();
+    expect($backup->s3_storage_id)->toBeNull();
+    expect($backup->disable_local_backup)->toBeFalsy();
+});
diff --git a/tests/Feature/CreateScheduledBackupValidationTest.php b/tests/Feature/CreateScheduledBackupValidationTest.php
new file mode 100644
index 000000000..a167511e2
--- /dev/null
+++ b/tests/Feature/CreateScheduledBackupValidationTest.php
@@ -0,0 +1,102 @@
+<?php
+
+use App\Livewire\Project\Database\CreateScheduledBackup;
+use App\Models\Environment;
+use App\Models\Project;
+use App\Models\S3Storage;
+use App\Models\ScheduledDatabaseBackup;
+use App\Models\Server;
+use App\Models\StandaloneDocker;
+use App\Models\StandalonePostgresql;
+use App\Models\Team;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Livewire\Livewire;
+
+uses(RefreshDatabase::class);
+
+function createDatabaseForScheduledBackupTest(Team $team): StandalonePostgresql
+{
+    $server = Server::factory()->create(['team_id' => $team->id]);
+    $destination = StandaloneDocker::where('server_id', $server->id)->firstOrFail();
+    $project = Project::factory()->create(['team_id' => $team->id]);
+    $environment = Environment::factory()->create(['project_id' => $project->id]);
+
+    return StandalonePostgresql::create([
+        'name' => 'pg-scheduled-backup-validation',
+        'image' => 'postgres:16-alpine',
+        'postgres_user' => 'postgres',
+        'postgres_password' => 'password',
+        'postgres_db' => 'postgres',
+        'environment_id' => $environment->id,
+        'destination_id' => $destination->id,
+        'destination_type' => $destination->getMorphClass(),
+    ]);
+}
+
+function createS3StorageForTeam(Team $team, string $name = 'Test S3'): S3Storage
+{
+    return S3Storage::create([
+        'name' => $name,
+        'region' => 'us-east-1',
+        'key' => 'test-key',
+        'secret' => 'test-secret',
+        'bucket' => 'test-bucket',
+        'endpoint' => 'https://s3.example.com',
+        'is_usable' => true,
+        'team_id' => $team->id,
+    ]);
+}
+
+beforeEach(function () {
+    $this->team = Team::factory()->create();
+    $this->user = User::factory()->create();
+    $this->user->teams()->attach($this->team, ['role' => 'owner']);
+    $this->actingAs($this->user);
+    session(['currentTeam' => $this->team]);
+});
+
+it('rejects enabling S3 backup without a selected S3 storage', function () {
+    $database = createDatabaseForScheduledBackupTest($this->team);
+
+    Livewire::test(CreateScheduledBackup::class, ['database' => $database])
+        ->set('frequency', '0 0 * * *')
+        ->set('saveToS3', true)
+        ->set('s3StorageId', null)
+        ->call('submit')
+        ->assertDispatched('error');
+
+    expect(ScheduledDatabaseBackup::count())->toBe(0);
+});
+
+it('rejects an S3 storage not owned by the current team', function () {
+    $database = createDatabaseForScheduledBackupTest($this->team);
+
+    $foreignS3 = createS3StorageForTeam(Team::factory()->create(), 'Foreign S3');
+
+    Livewire::test(CreateScheduledBackup::class, ['database' => $database])
+        ->set('frequency', '0 0 * * *')
+        ->set('saveToS3', true)
+        ->set('s3StorageId', $foreignS3->id)
+        ->call('submit')
+        ->assertDispatched('error');
+
+    expect(ScheduledDatabaseBackup::count())->toBe(0);
+});
+
+it('creates a scheduled backup with a valid team-owned S3 storage', function () {
+    $database = createDatabaseForScheduledBackupTest($this->team);
+    $s3 = createS3StorageForTeam($this->team);
+
+    Livewire::test(CreateScheduledBackup::class, ['database' => $database])
+        ->set('frequency', '0 0 * * *')
+        ->set('saveToS3', true)
+        ->set('s3StorageId', $s3->id)
+        ->call('submit')
+        ->assertDispatched('refreshScheduledBackups');
+
+    $backup = ScheduledDatabaseBackup::first();
+    expect($backup)->not->toBeNull();
+    expect($backup->save_s3)->toBeTruthy();
+    expect($backup->s3_storage_id)->toBe($s3->id);
+});
diff --git a/tests/Feature/DatabaseBackupJobTest.php b/tests/Feature/DatabaseBackupJobTest.php
index 05cb21f12..2d549c1ca 100644
--- a/tests/Feature/DatabaseBackupJobTest.php
+++ b/tests/Feature/DatabaseBackupJobTest.php
@@ -66,6 +66,48 @@ test('upload_to_s3 throws exception and disables s3 when storage is null', funct
     expect($backup->s3_storage_id)->toBeNull();
 });
 
+test('upload_to_s3 exception message reports the previous s3 storage id', function () {
+    $backup = ScheduledDatabaseBackup::create([
+        'frequency' => '0 0 * * *',
+        'save_s3' => true,
+        's3_storage_id' => 12345,
+        'database_type' => 'App\Models\StandalonePostgresql',
+        'database_id' => 1,
+        'team_id' => Team::factory()->create()->id,
+    ]);
+
+    $job = new DatabaseBackupJob($backup);
+
+    $reflection = new ReflectionClass($job);
+    $reflection->getProperty('s3')->setValue($job, null);
+
+    expect(fn () => $reflection->getMethod('upload_to_s3')->invoke($job))
+        ->toThrow(Exception::class, 'S3 storage ID: 12345');
+
+    $backup->refresh();
+    expect($backup->save_s3)->toBeFalsy();
+    expect($backup->s3_storage_id)->toBeNull();
+});
+
+test('upload_to_s3 exception message reports null when no previous s3 storage id exists', function () {
+    $backup = ScheduledDatabaseBackup::create([
+        'frequency' => '0 0 * * *',
+        'save_s3' => true,
+        's3_storage_id' => null,
+        'database_type' => 'App\Models\StandalonePostgresql',
+        'database_id' => 1,
+        'team_id' => Team::factory()->create()->id,
+    ]);
+
+    $job = new DatabaseBackupJob($backup);
+
+    $reflection = new ReflectionClass($job);
+    $reflection->getProperty('s3')->setValue($job, null);
+
+    expect(fn () => $reflection->getMethod('upload_to_s3')->invoke($job))
+        ->toThrow(Exception::class, 'S3 storage ID: null');
+});
+
 test('deleting s3 storage disables s3 on linked backups', function () {
     $team = Team::factory()->create();