diff --git a/core/config/schema/core.entity.schema.yml b/core/config/schema/core.entity.schema.yml
index 57e55472555e8958abcda3a67c2c5b53e8b6cd55..81c03dbca0745d79ff4933e90796e52363201a68 100644
--- a/core/config/schema/core.entity.schema.yml
+++ b/core/config/schema/core.entity.schema.yml
@@ -379,3 +379,33 @@ block.settings.field_block:*:*:*:
 action.configuration.entity:*:*:
   type: action_configuration_default
   label: 'Entity action'
+
+action.configuration.action_send_email_action:
+  type: mapping
+  label: 'Send email configuration'
+  mapping:
+    recipient:
+      type: string
+      label: 'Recipient'
+    subject:
+      type: label
+      label: 'Subject'
+    message:
+      type: text
+      label: 'Message'
+
+action.configuration.action_goto_action:
+  type: mapping
+  label: 'Redirect to URL configuration'
+  mapping:
+    url:
+      type: string
+      label: 'URL'
+
+action.configuration.action_message_action:
+  type: mapping
+  label: 'Display a message to the user configuration'
+  mapping:
+    message:
+      type: text
+      label: 'Message'
diff --git a/core/modules/action/src/Plugin/Action/EmailAction.php b/core/lib/Drupal/Core/Action/Plugin/Action/EmailAction.php
similarity index 99%
rename from core/modules/action/src/Plugin/Action/EmailAction.php
rename to core/lib/Drupal/Core/Action/Plugin/Action/EmailAction.php
index 0791a3f99889a7ec438826f106933cbc7d3b41f8..0f8a4575febf396bd50a798824f753c24889e31b 100644
--- a/core/modules/action/src/Plugin/Action/EmailAction.php
+++ b/core/lib/Drupal/Core/Action/Plugin/Action/EmailAction.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\action\Plugin\Action;
+namespace Drupal\Core\Action\Plugin\Action;
 
 use Drupal\Component\Render\PlainTextOutput;
 use Drupal\Component\Utility\EmailValidatorInterface;
diff --git a/core/modules/action/src/Plugin/Action/GotoAction.php b/core/lib/Drupal/Core/Action/Plugin/Action/GotoAction.php
similarity index 99%
rename from core/modules/action/src/Plugin/Action/GotoAction.php
rename to core/lib/Drupal/Core/Action/Plugin/Action/GotoAction.php
index ce9a4e3f6eec9179c37b8be481aae40ff95638fe..b19a3d991cdc14b3b334c2531ae71e54a75872a4 100644
--- a/core/modules/action/src/Plugin/Action/GotoAction.php
+++ b/core/lib/Drupal/Core/Action/Plugin/Action/GotoAction.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\action\Plugin\Action;
+namespace Drupal\Core\Action\Plugin\Action;
 
 use Drupal\Component\Utility\UrlHelper;
 use Drupal\Core\Access\AccessResult;
diff --git a/core/modules/action/src/Plugin/Action/MessageAction.php b/core/lib/Drupal/Core/Action/Plugin/Action/MessageAction.php
similarity index 98%
rename from core/modules/action/src/Plugin/Action/MessageAction.php
rename to core/lib/Drupal/Core/Action/Plugin/Action/MessageAction.php
index 9309fc926acd2f75cf37a02cce8799bb85577f4d..7c892eeed23955ba85937eba64400bd7aec7fe12 100644
--- a/core/modules/action/src/Plugin/Action/MessageAction.php
+++ b/core/lib/Drupal/Core/Action/Plugin/Action/MessageAction.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\action\Plugin\Action;
+namespace Drupal\Core\Action\Plugin\Action;
 
 use Drupal\Core\Access\AccessResult;
 use Drupal\Core\Action\ConfigurableActionBase;
diff --git a/core/modules/action/action.post_udate.php b/core/modules/action/action.post_udate.php
new file mode 100644
index 0000000000000000000000000000000000000000..b88b0dbcace0ecfb4758edc901d1bacf6709899e
--- /dev/null
+++ b/core/modules/action/action.post_udate.php
@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * @file
+ * Post update functions for Action module.
+ */
+
+use Drupal\Core\Config\Entity\ConfigEntityUpdater;
+use Drupal\system\ActionConfigEntityInterface;
+
+/**
+ * Moves action plugins to core.
+ */
+function action_post_update_move_plugins(&$sandbox = NULL) {
+  $resave_ids = [
+    'action_goto_action',
+    'action_message_action',
+    'action_send_email_action',
+  ];
+  \Drupal::classResolver(ConfigEntityUpdater::class)->update($sandbox, 'action', function (ActionConfigEntityInterface $action) use ($resave_ids) {
+    // Save entity to recalculate dependencies.
+    return $action->isConfigurable() && in_array($action->getPlugin()->getPluginId(), $resave_ids, TRUE);
+  });
+}
diff --git a/core/modules/action/config/schema/action.schema.yml b/core/modules/action/config/schema/action.schema.yml
index 421e05fd18297352d440f597045226e7b4f21349..934df120f4734cabb2201e9e3fb7dc4c9b011ab4 100644
--- a/core/modules/action/config/schema/action.schema.yml
+++ b/core/modules/action/config/schema/action.schema.yml
@@ -7,34 +7,3 @@ action.settings:
     recursion_limit:
       type: integer
       label: 'Recursion limit for actions'
-
-
-action.configuration.action_send_email_action:
-  type: mapping
-  label: 'Send email configuration'
-  mapping:
-    recipient:
-      type: string
-      label: 'Recipient'
-    subject:
-      type: label
-      label: 'Subject'
-    message:
-      type: text
-      label: 'Message'
-
-action.configuration.action_goto_action:
-  type: mapping
-  label: 'Redirect to URL configuration'
-  mapping:
-    url:
-      type: string
-      label: 'URL'
-
-action.configuration.action_message_action:
-  type: mapping
-  label: 'Display a message to the user configuration'
-  mapping:
-    message:
-      type: text
-      label: 'Message'
diff --git a/core/modules/system/tests/fixtures/update/drupal-8.actions-2815379.php b/core/modules/system/tests/fixtures/update/drupal-8.actions-2815379.php
new file mode 100644
index 0000000000000000000000000000000000000000..c76a840fcb3604406b1e7ef595f1df9706a62925
--- /dev/null
+++ b/core/modules/system/tests/fixtures/update/drupal-8.actions-2815379.php
@@ -0,0 +1,47 @@
+<?php
+
+/**
+ * @file
+ * Contains database additions to for testing upgrade path for action plugins.
+ *
+ * @see https://www.drupal.org/node/2815379
+ */
+
+use Drupal\Core\Database\Database;
+use Drupal\Core\Serialization\Yaml;
+
+$connection = Database::getConnection();
+
+// Structure of configured email, goto, and message actions.
+$actions[] = Yaml::decode(file_get_contents(__DIR__ . '/system.action.goto_2815379.yml'));
+$actions[] = Yaml::decode(file_get_contents(__DIR__ . '/system.action.message_2815379.yml'));
+$actions[] = Yaml::decode(file_get_contents(__DIR__ . '/system.action.send_email_2815379.yml'));
+
+foreach ($actions as $action) {
+  $connection->insert('config')
+    ->fields([
+      'collection',
+      'name',
+      'data',
+    ])
+    ->values([
+      'collection' => '',
+      'name' => 'system.action.' . $action['id'],
+      'data' => serialize($action),
+    ])
+    ->execute();
+}
+
+// Enable action module.
+$extensions = $connection->select('config')
+  ->fields('config', ['data'])
+  ->condition('name', 'core.extension')
+  ->execute()
+  ->fetchField();
+$extensions = unserialize($extensions);
+$connection->update('config')
+  ->fields([
+    'data' => serialize(array_merge_recursive($extensions, ['module' => ['action' => 0]])),
+  ])
+  ->condition('name', 'core.extension')
+  ->execute();
diff --git a/core/modules/system/tests/fixtures/update/system.action.goto_2815379.yml b/core/modules/system/tests/fixtures/update/system.action.goto_2815379.yml
new file mode 100644
index 0000000000000000000000000000000000000000..1186ec9472893a9249da8f640c1febfb830be6ef
--- /dev/null
+++ b/core/modules/system/tests/fixtures/update/system.action.goto_2815379.yml
@@ -0,0 +1,12 @@
+uuid: 2573293e-c7b6-4f53-905a-10ec7c55f3d0
+langcode: en
+status: true
+dependencies:
+  module:
+    - action
+id: goto_2815379
+label: 'Goto action'
+type: system
+plugin: action_goto_action
+configuration:
+  url: /user
diff --git a/core/modules/system/tests/fixtures/update/system.action.message_2815379.yml b/core/modules/system/tests/fixtures/update/system.action.message_2815379.yml
new file mode 100644
index 0000000000000000000000000000000000000000..01b51cee7027cf9f40e15474969ed61b91777642
--- /dev/null
+++ b/core/modules/system/tests/fixtures/update/system.action.message_2815379.yml
@@ -0,0 +1,12 @@
+uuid: e34302d4-3afc-40ec-bdf0-cbd23e2f7f52
+langcode: en
+status: true
+dependencies:
+  module:
+    - action
+id: message_2815379
+label: 'Display message'
+type: system
+plugin: action_message_action
+configuration:
+  message: 'Test message'
diff --git a/core/modules/system/tests/fixtures/update/system.action.send_email_2815379.yml b/core/modules/system/tests/fixtures/update/system.action.send_email_2815379.yml
new file mode 100644
index 0000000000000000000000000000000000000000..7651bcafdd97beca04659a72cf64969c343447b5
--- /dev/null
+++ b/core/modules/system/tests/fixtures/update/system.action.send_email_2815379.yml
@@ -0,0 +1,14 @@
+uuid: 741d330c-9260-45f8-8a81-67d2cd430f4a
+langcode: en
+status: true
+dependencies:
+  module:
+    - action
+id: send_email_2815379
+label: 'Send email'
+type: system
+plugin: action_send_email_action
+configuration:
+  recipient: drupal@example.com
+  subject: Subject
+  message: Message
diff --git a/core/modules/system/tests/src/Functional/Update/MoveActionsToCoreTest.php b/core/modules/system/tests/src/Functional/Update/MoveActionsToCoreTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..4d191994b8834075dde3b37dfc266fd0c4e9d795
--- /dev/null
+++ b/core/modules/system/tests/src/Functional/Update/MoveActionsToCoreTest.php
@@ -0,0 +1,56 @@
+<?php
+
+namespace Drupal\Tests\system\Functional\Update;
+
+use Drupal\FunctionalTests\Update\UpdatePathTestBase;
+use Drupal\system\Entity\Action;
+
+/**
+ * Tests moving email, goto, and message actions to core namespace.
+ *
+ * @group Update
+ * @group legacy
+ */
+class MoveActionsToCoreTest extends UpdatePathTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setDatabaseDumpFiles() {
+    $this->databaseDumpFiles = [
+      __DIR__ . '/../../../../tests/fixtures/update/drupal-8.bare.standard.php.gz',
+      __DIR__ . '/../../../../tests/fixtures/update/drupal-8.actions-2815379.php',
+    ];
+  }
+
+  /**
+   * Tests upgrading actions to core namespace.
+   *
+   * @see action_post_update_move_plugins()
+   */
+  public function testUpdateActionPlugins() {
+    $actions = ['goto_2815379', 'message_2815379', 'send_email_2815379'];
+    $before = [];
+
+    $dependencies = ['module' => ['action']];
+    foreach ($actions as $key) {
+      $config = \Drupal::configFactory()->get('system.action.' . $key);
+      $this->assertSame($dependencies, $config->get('dependencies'));
+      $before[$key] = $config->getRawData();
+    }
+
+    $this->runUpdates();
+
+    foreach ($actions as $key) {
+      /** @var \Drupal\system\Entity\Action $key */
+      $action = Action::load($key);
+      $this->assertSame([], $action->getDependencies());
+      // Tests that other properties remains the same.
+      $config = \Drupal::configFactory()->get('system.action.' . $key);
+      $after = $before[$key];
+      $after['dependencies'] = [];
+      $this->assertSame($after, $config->getRawData());
+    }
+  }
+
+}
diff --git a/core/modules/action/tests/src/Kernel/Plugin/Action/EmailActionTest.php b/core/tests/Drupal/KernelTests/Core/Action/EmailActionTest.php
similarity index 93%
rename from core/modules/action/tests/src/Kernel/Plugin/Action/EmailActionTest.php
rename to core/tests/Drupal/KernelTests/Core/Action/EmailActionTest.php
index a47f9b35f74e5aaa70f4f7f92db6fac8def2f26d..22bd3bbe3071eaf31590cedfbbc9718665e7dc12 100644
--- a/core/modules/action/tests/src/Kernel/Plugin/Action/EmailActionTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Action/EmailActionTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\Tests\action\Kernel\Plugin\Action;
+namespace Drupal\KernelTests\Core\Action;
 
 use Drupal\Core\Test\AssertMailTrait;
 use Drupal\KernelTests\KernelTestBase;
@@ -16,7 +16,7 @@ class EmailActionTest extends KernelTestBase {
   /**
    * {@inheritdoc}
    */
-  public static $modules = ['system', 'user', 'action', 'dblog'];
+  public static $modules = ['system', 'user', 'dblog'];
 
   /**
    * {@inheritdoc}