diff --git a/types/firestore.d.ts b/types/firestore.d.ts
index eaa0d85bd..92d8477ed 100644
--- a/types/firestore.d.ts
+++ b/types/firestore.d.ts
@@ -510,6 +510,11 @@ declare namespace FirebaseFirestore {
      */
     settings(settings: Settings): void;
 
+    /**
+     * Returns the Database ID for this Firestore instance.
+     */
+    get databaseId(): string;
+
     /**
      * Gets a `CollectionReference` instance that refers to the collection at
      * the specified path.