diff --git a/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php b/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php
index 07a5b1bd7eb..5f6ebe481b6 100644
--- a/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php
+++ b/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php
@@ -26,6 +26,7 @@ use Symfony\Component\Yaml\Yaml;
  * Tests different ways of enabling CKEditor 5 plugins.
  *
  * @group ckeditor5
+ * @group #slow
  * @internal
  */
 class CKEditor5PluginManagerTest extends KernelTestBase {
diff --git a/core/modules/ckeditor5/tests/src/Kernel/ValidatorsTest.php b/core/modules/ckeditor5/tests/src/Kernel/ValidatorsTest.php
index dac6a409510..09e8bc7e4e4 100644
--- a/core/modules/ckeditor5/tests/src/Kernel/ValidatorsTest.php
+++ b/core/modules/ckeditor5/tests/src/Kernel/ValidatorsTest.php
@@ -24,6 +24,7 @@ use Symfony\Component\Yaml\Yaml;
  * @covers \Drupal\ckeditor5\Plugin\Validation\Constraint\FundamentalCompatibilityConstraintValidator
  * @covers \Drupal\ckeditor5\Plugin\Validation\Constraint\CKEditor5MediaAndFilterSettingsInSyncConstraintValidator
  * @group ckeditor5
+ * @group #slow
  */
 class ValidatorsTest extends KernelTestBase {
 
diff --git a/core/modules/content_moderation/tests/src/Kernel/ContentModerationStateTest.php b/core/modules/content_moderation/tests/src/Kernel/ContentModerationStateTest.php
index dc629d73b16..33740c2088f 100644
--- a/core/modules/content_moderation/tests/src/Kernel/ContentModerationStateTest.php
+++ b/core/modules/content_moderation/tests/src/Kernel/ContentModerationStateTest.php
@@ -21,6 +21,7 @@ use Drupal\workflows\Entity\Workflow;
  * Tests links between a content entity and a content_moderation_state entity.
  *
  * @group content_moderation
+ * @group #slow
  */
 class ContentModerationStateTest extends KernelTestBase {
 
diff --git a/core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php b/core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php
index 159b6679743..17ca312e383 100644
--- a/core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php
+++ b/core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php
@@ -16,6 +16,7 @@ use PHPUnit\Framework\AssertionFailedError;
  * Tests the new entity API for the date field type.
  *
  * @group datetime
+ * @group #slow
  */
 class DateTimeItemTest extends FieldKernelTestBase {
 
diff --git a/core/modules/field/tests/src/Kernel/Number/NumberItemTest.php b/core/modules/field/tests/src/Kernel/Number/NumberItemTest.php
index 0ccef5319f8..365a52895ca 100644
--- a/core/modules/field/tests/src/Kernel/Number/NumberItemTest.php
+++ b/core/modules/field/tests/src/Kernel/Number/NumberItemTest.php
@@ -15,6 +15,7 @@ use Drupal\field\Entity\FieldStorageConfig;
  * Tests the new entity API for the number field type.
  *
  * @group field
+ * @group #slow
  */
 class NumberItemTest extends FieldKernelTestBase {
 
diff --git a/core/modules/media/tests/src/Kernel/MediaAccessControlHandlerTest.php b/core/modules/media/tests/src/Kernel/MediaAccessControlHandlerTest.php
index af64534a649..378d76a5631 100644
--- a/core/modules/media/tests/src/Kernel/MediaAccessControlHandlerTest.php
+++ b/core/modules/media/tests/src/Kernel/MediaAccessControlHandlerTest.php
@@ -11,6 +11,7 @@ use Drupal\Tests\user\Traits\UserCreationTrait;
  * Tests the media access control handler.
  *
  * @group media
+ * @group #slow
  *
  * @coversDefaultClass \Drupal\media\MediaAccessControlHandler
  */
diff --git a/core/modules/system/tests/src/Kernel/Entity/EntityReferenceSelectionReferenceableTest.php b/core/modules/system/tests/src/Kernel/Entity/EntityReferenceSelectionReferenceableTest.php
index d9be4d2a1e0..433604bb136 100644
--- a/core/modules/system/tests/src/Kernel/Entity/EntityReferenceSelectionReferenceableTest.php
+++ b/core/modules/system/tests/src/Kernel/Entity/EntityReferenceSelectionReferenceableTest.php
@@ -14,6 +14,7 @@ use Drupal\Tests\field\Traits\EntityReferenceFieldCreationTrait;
  * Tests entity reference selection plugins.
  *
  * @group entity_reference
+ * @group #slow
  */
 class EntityReferenceSelectionReferenceableTest extends KernelTestBase {
 
diff --git a/core/tests/Drupal/KernelTests/Core/Config/SimpleConfigValidationTest.php b/core/tests/Drupal/KernelTests/Core/Config/SimpleConfigValidationTest.php
index f714ab65f70..61e3e284785 100644
--- a/core/tests/Drupal/KernelTests/Core/Config/SimpleConfigValidationTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Config/SimpleConfigValidationTest.php
@@ -11,6 +11,7 @@ use Drupal\KernelTests\KernelTestBase;
  *
  * @group config
  * @group Validation
+ * @group #slow
  */
 class SimpleConfigValidationTest extends KernelTestBase {
 
diff --git a/core/tests/Drupal/KernelTests/Core/Entity/EntityViewDisplayValidationTest.php b/core/tests/Drupal/KernelTests/Core/Entity/EntityViewDisplayValidationTest.php
index 58c01c69bc2..8ae892b12c4 100644
--- a/core/tests/Drupal/KernelTests/Core/Entity/EntityViewDisplayValidationTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Entity/EntityViewDisplayValidationTest.php
@@ -15,6 +15,7 @@ use Drupal\Tests\node\Traits\ContentTypeCreationTrait;
  *
  * @group Entity
  * @group Validation
+ * @group #slow
  */
 class EntityViewDisplayValidationTest extends ConfigEntityValidationTestBase {