diff --git a/core/core.libraries.yml b/core/core.libraries.yml
index 8951785cc6..2a2e5bc47a 100644
--- a/core/core.libraries.yml
+++ b/core/core.libraries.yml
@@ -471,6 +471,7 @@ drupal.customevent:
     misc/polyfills/customevent.js: { weight: -20 }
 
 drupal.date:
+  deprecated: The "%library_id%" asset library is deprecated in drupal:9.4.0 and is removed from drupal:10.0.0. There is no replacement. See https://www.drupal.org/node/3258267
   version: VERSION
   js:
     misc/date.js: {}
diff --git a/core/lib/Drupal/Core/Render/Element/Date.php b/core/lib/Drupal/Core/Render/Element/Date.php
index 887f5d3905..86f6413c62 100644
--- a/core/lib/Drupal/Core/Render/Element/Date.php
+++ b/core/lib/Drupal/Core/Render/Element/Date.php
@@ -58,8 +58,14 @@ public function getInfo() {
    *
    * @return array
    *   The processed element.
+   *
+   * @deprecated in drupal:9.4.0 and is removed from drupal:10.0.0. There is
+   *   no replacement.
+   *
+   * @see https://www.drupal.org/node/3258267
    */
   public static function processDate(&$element, FormStateInterface $form_state, &$complete_form) {
+    @trigger_error('Drupal\Core\Render\Element\Date::processDate() is deprecated in drupal:9.4.0 and is removed from drupal:10.0.0. There is no replacement. See https://www.drupal.org/node/3258267', E_USER_DEPRECATED);
     // Attach JS support for the date field, if we can determine which date
     // format should be used.
     if ($element['#attributes']['type'] == 'date' && !empty($element['#date_date_format'])) {
diff --git a/core/tests/Drupal/Tests/Core/Render/Element/DateElementTest.php b/core/tests/Drupal/Tests/Core/Render/Element/DateElementTest.php
new file mode 100644
index 0000000000..479f5428d3
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Render/Element/DateElementTest.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace Drupal\Tests\Core\Render\Element;
+
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Render\Element\Date;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\Core\Render\Element\Date
+ * @group Render
+ */
+class DateElementTest extends UnitTestCase {
+
+  /**
+   * @covers ::processDate
+   * @group legacy
+   */
+  public function testProcessDate(): void {
+    $element = [
+      '#attributes' => ['type' => 'date'],
+      '#date_date_format' => 'Y-m-d',
+    ];
+    $complete_form = [];
+    $this->expectDeprecation('Drupal\Core\Render\Element\Date::processDate() is deprecated in drupal:9.4.0 and is removed from drupal:10.0.0. There is no replacement. See https://www.drupal.org/node/3258267');
+    Date::processDate($element, $this->createMock(FormStateInterface::class), $complete_form);
+  }
+
+}