diff --git a/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php b/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php
index 07a5b1bd7eb8c1dd1975640f5c061139326c311d..5f6ebe481b69a9511c845b42255fd2ef95eb3d44 100644
--- a/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php
+++ b/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php
@@ -26,6 +26,7 @@
  * 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 dac6a40951077f266253ce3df32ab433706270be..09e8bc7e4e410a84969b9871b48048406f712c76 100644
--- a/core/modules/ckeditor5/tests/src/Kernel/ValidatorsTest.php
+++ b/core/modules/ckeditor5/tests/src/Kernel/ValidatorsTest.php
@@ -24,6 +24,7 @@
  * @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 dc629d73b16a503e732f3a80192a65001d62bb27..33740c2088fd5f92e3b0f5cb55c18a0a368cc5e7 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 @@
  * 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 159b66797436463b55b969fe342ef91f018cb56e..17ca312e3838f7aaa47f82437e54409940d022fb 100644
--- a/core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php
+++ b/core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php
@@ -16,6 +16,7 @@
  * 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 0ccef5319f8c4088c6fcc468067f1b9b854c0f1a..365a52895caedbe66544bd5d7b9f34dd62273d5b 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 @@
  * 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 af64534a6493da538e131f141598e5980b87fba4..378d76a5631bea8cde370d12586bd9d61860c246 100644
--- a/core/modules/media/tests/src/Kernel/MediaAccessControlHandlerTest.php
+++ b/core/modules/media/tests/src/Kernel/MediaAccessControlHandlerTest.php
@@ -11,6 +11,7 @@
  * 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 d9be4d2a1e008ce3f15faad4d70e7b1074c888ee..433604bb136332da5f54c9936d69590a43646c7b 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 @@
  * 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 f714ab65f707065b80132880ab698a411457c441..61e3e2847855cc390d510b5e415fafdc68e560f9 100644
--- a/core/tests/Drupal/KernelTests/Core/Config/SimpleConfigValidationTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Config/SimpleConfigValidationTest.php
@@ -11,6 +11,7 @@
  *
  * @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 58c01c69bc25598fbc994055ed03d49a303f2b00..8ae892b12c41580b73438670a74aff670794ee2a 100644
--- a/core/tests/Drupal/KernelTests/Core/Entity/EntityViewDisplayValidationTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Entity/EntityViewDisplayValidationTest.php
@@ -15,6 +15,7 @@
  *
  * @group Entity
  * @group Validation
+ * @group #slow
  */
 class EntityViewDisplayValidationTest extends ConfigEntityValidationTestBase {