diff --git a/lib/experimental/fonts/font-library/class-wp-font-library.php b/lib/experimental/fonts/font-library/class-wp-font-library.php
index aab7bcee79a7e1..346cf10014541b 100644
--- a/lib/experimental/fonts/font-library/class-wp-font-library.php
+++ b/lib/experimental/fonts/font-library/class-wp-font-library.php
@@ -52,6 +52,15 @@ public static function get_expected_font_mime_types_per_php_version( $php_versio
 	 */
 	private static $collections = array();
 
+	/**
+	 * Unregistered font collections ids.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @var array
+	 */
+	private static $unregistered_collection_ids = array();
+
 	/**
 	 * Register a new font collection.
 	 *
@@ -81,11 +90,7 @@ public static function register_font_collection( $config ) {
 	 * @return bool True if the font collection was unregistered successfully and false otherwise.
 	 */
 	public static function unregister_font_collection( $collection_id ) {
-		if ( ! isset( self::$collections[ $collection_id ] ) ) {
-			return false;
-		}
-		unset( self::$collections[ $collection_id ] );
-		return true;
+		self::$unregistered_collection_ids[] = $collection_id;
 	}
 
 	/**
@@ -96,7 +101,14 @@ public static function unregister_font_collection( $collection_id ) {
 	 * @return array List of font collections.
 	 */
 	public static function get_font_collections() {
-		return self::$collections;
+		// filters collections to remove unregistered collections.
+		$registered_collections = array();
+		foreach ( self::$collections as $key => $value ) {
+			if ( ! in_array( $key, self::$unregistered_collection_ids, true ) ) {
+				$registered_collections[ $key ] = $value;
+			}
+		}
+		return $registered_collections;
 	}
 
 	/**
diff --git a/lib/experimental/fonts/font-library/font-library.php b/lib/experimental/fonts/font-library/font-library.php
index ea6f9c8394b513..bffc9d0a550409 100644
--- a/lib/experimental/fonts/font-library/font-library.php
+++ b/lib/experimental/fonts/font-library/font-library.php
@@ -66,13 +66,9 @@ function wp_register_font_collection( $config ) {
 	 * @param string $collection_id The font collection ID.
 	 */
 	function wp_unregister_font_collection( $collection_id ) {
-		add_action(
-			'init',
-			function () use ( $collection_id ) {
-				WP_Font_Library::unregister_font_collection( $collection_id );
-			}
-		);
+		WP_Font_Library::unregister_font_collection( $collection_id );
 	}
+
 }
 
 $default_font_collection = array(
diff --git a/phpunit/tests/fonts/font-library/wpFontLibrary/unregisterFontCollection.php b/phpunit/tests/fonts/font-library/wpFontLibrary/unregisterFontCollection.php
index 425a7e717cee37..927bc70443895d 100644
--- a/phpunit/tests/fonts/font-library/wpFontLibrary/unregisterFontCollection.php
+++ b/phpunit/tests/fonts/font-library/wpFontLibrary/unregisterFontCollection.php
@@ -13,36 +13,28 @@
 class Tests_Fonts_WpFontLibrary_UnregisterFontCollection extends WP_UnitTestCase {
 
 	public function set_up() {
-		$config     = array(
-			'id'             => 'mock-col-to-unregister',
-			'name'           => 'Mock Collection to be unregistered',
-			'description'    => 'A mock font collection to be unregistered.',
-			'data_json_file' => 'my-collection-data.json',
+		$config = array(
+			'id'          => 'mock-col-to-unregister',
+			'name'        => 'Mock Collection to be unregistered',
+			'description' => 'A mock font collection to be unregistered.',
+			'src'         => 'my-collection-data.json',
+		);
+		WP_Font_Library::register_font_collection( $config );
+
+		$config = array(
+			'id'          => 'another-collecction',
+			'name'        => 'Mock Collection',
+			'description' => 'A mock font collection.',
+			'src'         => 'my-mock-data.json',
 		);
 		WP_Font_Library::register_font_collection( $config );
 	}
 
 	public function test_should_unregister_font_collection() {
 		// Unregister mock font collection.
-		$result1 = WP_Font_Library::unregister_font_collection( 'mock-col-to-unregister' );
-		$this->assertTrue( $result1, 'Should return true if it was unregistered succesfully.' );
-		// Try to unregister mock font collection again.
-		$result2 = WP_Font_Library::unregister_font_collection( 'mock-col-to-unregister' );
-		$this->assertFalse( $result2, 'Should return false because it was already unregistered.' );
-	}
-
-	public function test_should_unregister_default_font_collection() {
-		// Unregister default font collection.
-		$result1 = WP_Font_Library::unregister_font_collection( 'default-font-collection' );
-		$this->assertTrue( $result1, 'Should return true if it was unregistered succesfully.' );
-		// Try to unregister default font collection again.
-		$result2 = WP_Font_Library::unregister_font_collection( 'default-font-collection' );
-		$this->assertFalse( $result2, 'Should return false because it was already unregistered.' );
-	}
-
-	public function test_should_unregister_non_existing_font_collection() {
-		// Unregister default font collection.
-		$result = WP_Font_Library::unregister_font_collection( 'fake-collection-id-x1234' );
-		$this->assertFalse( $result );
+		WP_Font_Library::unregister_font_collection( 'mock-col-to-unregister' );
+		$collections = WP_Font_Library::get_font_collections();
+		$this->assertArrayNotHasKey( 'mock-col-to-unregister', $collections, 'Font collection was not unregistered.' );
+		$this->assertArrayHasKey( 'default-font-collection', $collections, 'Font collection was unregistered by mistake.' );
 	}
 }