diff --git a/packages/react-scripts/template/src/registerServiceWorker.js b/packages/react-scripts/template/src/registerServiceWorker.js
index 4a3ccf02124..41308467b2e 100644
--- a/packages/react-scripts/template/src/registerServiceWorker.js
+++ b/packages/react-scripts/template/src/registerServiceWorker.js
@@ -21,7 +21,7 @@ const isLocalhost = Boolean(
 export default function register() {
   if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) {
     // The URL constructor is available in all browsers that support SW.
-    const publicUrl = new URL(process.env.PUBLIC_URL, window.location);
+    const publicUrl = new window.URL(process.env.PUBLIC_URL, window.location);
     if (publicUrl.origin !== window.location.origin) {
       // Our service worker won't work if PUBLIC_URL is on a different origin
       // from what our page is served on. This might happen if a CDN is used to
@@ -74,7 +74,7 @@ function registerValidSW(swUrl) {
 
 function checkValidServiceWorker(swUrl) {
   // Check if the service worker can be found. If it can't reload the page.
-  fetch(swUrl)
+  window.fetch(swUrl)
     .then(response => {
       // Ensure service worker exists, and that we really are getting a JS file.
       if (
@@ -100,8 +100,8 @@ function checkValidServiceWorker(swUrl) {
 }
 
 export function unregister() {
-  if ('serviceWorker' in navigator) {
-    navigator.serviceWorker.ready.then(registration => {
+  if ('serviceWorker' in window.navigator) {
+    window.navigator.serviceWorker.ready.then(registration => {
       registration.unregister();
     });
   }