diff --git a/.changeset/purple-cooks-explode.md b/.changeset/purple-cooks-explode.md
new file mode 100644
index 00000000000..7507ae5717a
--- /dev/null
+++ b/.changeset/purple-cooks-explode.md
@@ -0,0 +1,5 @@
+---
+'@firebase/util': patch
+---
+
+Fix isSafari() throwing on React Native
diff --git a/packages/util/src/environment.ts b/packages/util/src/environment.ts
index 04bbd92165d..f2afaede0f1 100644
--- a/packages/util/src/environment.ts
+++ b/packages/util/src/environment.ts
@@ -138,6 +138,7 @@ export function isNodeSdk(): boolean {
 export function isSafari(): boolean {
   return (
     !isNode() &&
+    !!navigator.userAgent &&
     navigator.userAgent.includes('Safari') &&
     !navigator.userAgent.includes('Chrome')
   );