diff -u b/core/modules/layout_builder/src/Section.php b/core/modules/layout_builder/src/Section.php
--- b/core/modules/layout_builder/src/Section.php
+++ b/core/modules/layout_builder/src/Section.php
@@ -16,7 +16,7 @@
  * @see \Drupal\Core\Layout\LayoutDefinition
  * @see \Drupal\layout_builder\SectionComponent
  */
-class Section implements ThirdPartySettingsInterface {
+class Section implements ThirdPartySettingsInterface, \JsonSerializable {
 
   /**
    * The layout plugin ID.
@@ -441,2 +441,11 @@
 
+  /**
+   * Returns a representation of the section for use in JSON serialization.
+   *
+   * @return array
+   */
+  public function jsonSerialize() {
+    return $this->toArray();
+  }
+
 }