diff --git a/authentication/AuthenticationExample/ViewControllers/UserViewController.swift b/authentication/AuthenticationExample/ViewControllers/UserViewController.swift
index 365dc7364..79d45be42 100644
--- a/authentication/AuthenticationExample/ViewControllers/UserViewController.swift
+++ b/authentication/AuthenticationExample/ViewControllers/UserViewController.swift
@@ -13,7 +13,8 @@
 // limitations under the License.
 
 import UIKit
-import FirebaseAuth
+// TODO: Remove @preconcurrency once `FirebaseAuth.User` is Sendable
+@preconcurrency import FirebaseAuth
 import AuthenticationServices
 import CryptoKit