diff --git a/core/modules/serialization/serialization.services.yml b/core/modules/serialization/serialization.services.yml
index 3a1ea4a..f3c3137 100644
--- a/core/modules/serialization/serialization.services.yml
+++ b/core/modules/serialization/serialization.services.yml
@@ -69,3 +69,8 @@ services:
     tags:
       - { name: event_subscriber }
     arguments: ['@serializer', '%serializer.formats%']
+  serialization.user_last_access_subscriber:
+    class: Drupal\serialization\EventSubscriber\UserRouteAlterSubscriber
+    tags:
+      - { name: event_subscriber }
+    arguments: ['@serializer', '%serializer.formats%']
diff --git a/core/modules/serialization/src/EventSubscriber/ExceptionHttpSubscriber.php b/core/modules/serialization/src/EventSubscriber/ExceptionHttpSubscriber.php
index 23a72b6..9b4cba2 100644
--- a/core/modules/serialization/src/EventSubscriber/ExceptionHttpSubscriber.php
+++ b/core/modules/serialization/src/EventSubscriber/ExceptionHttpSubscriber.php
@@ -13,7 +13,7 @@
 class ExceptionHttpSubscriber extends HttpExceptionSubscriberBase {
 
   /**
-   * The Serializer.
+   * The serializer.
    *
    * @var \Symfony\Component\Serializer\Serializer
    */
diff --git a/core/modules/serialization/src/EventSubscriber/UserRouteAlterSubscriber.php b/core/modules/serialization/src/EventSubscriber/UserRouteAlterSubscriber.php
new file mode 100644
index 0000000..dd6e2a7
--- /dev/null
+++ b/core/modules/serialization/src/EventSubscriber/UserRouteAlterSubscriber.php
@@ -0,0 +1,72 @@
+<?php
+
+namespace Drupal\serialization\EventSubscriber;
+
+
+use Drupal\Core\Routing\RouteBuildEvent;
+use Drupal\Core\Routing\RoutingEvents;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\Serializer\SerializerInterface;
+
+/**
+ * Alters user authentication routes to add formats supported by this module.
+ */
+class UserRouteAlterSubscriber implements EventSubscriberInterface {
+
+  /**
+   * The serializer.
+   *
+   * @var \Symfony\Component\Serializer\Serializer
+   */
+  protected $serializer;
+
+  /**
+   * The available serialization formats.
+   *
+   * @var array
+   */
+  protected $serializerFormats = array();
+
+  /**
+   * UserRouteAlterSubscriber constructor.
+   *
+   * @param \Symfony\Component\Serializer\SerializerInterface $serializer
+   *   The serializer service.
+   * @param array $serializer_formats
+   *   The available serializer formats.
+   */
+  public function __construct(SerializerInterface $serializer, array $serializer_formats) {
+    $this->serializer = $serializer;
+    $this->serializerFormats = $serializer_formats;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    $events[RoutingEvents::ALTER][] = 'onRoutingRouteAlterAddFormats';
+    return $events;
+  }
+
+  /**
+   * Adds supported formats to the user authentication http routes.
+   *
+   * @param \Drupal\Core\Routing\RouteBuildEvent $event
+   *   The event to process.
+   */
+  public function onRoutingRouteAlterAddFormats(RouteBuildEvent $event) {
+    $route_names = [
+      'user.login_status.http',
+      'user.login.http',
+      'user.logout.http',
+    ];
+    $routes = $event->getRouteCollection();
+    foreach ($route_names as $route_name) {
+      $route = $routes->get($route_name);
+      $formats = explode('|', $route->getRequirement('_format'));
+      $formats = array_unique($formats + $this->serializerFormats);
+      $route->setRequirement('_format', implode('|', $formats));
+    }
+  }
+
+}