diff --git a/Libraries/Blob/URL.js b/Libraries/Blob/URL.js
index 9869dcbeade..f2b6f7f277c 100644
--- a/Libraries/Blob/URL.js
+++ b/Libraries/Blob/URL.js
@@ -107,7 +107,7 @@ export class URLSearchParams {
 
 function validateBaseUrl(url: string) {
   // from this MIT-licensed gist: https://gist.github.com/dperini/729294
-  return /^(?:(?:(?:https?|ftp):)?\/\/)(?:(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,})))(?::\d{2,5})?(?:[/?#]\S*)?$/i.test(
+  return /^(?:(?:(?:https?|ftp):)?\/\/)(?:(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,}))?)(?::\d{2,5})?(?:[/?#]\S*)?$/i.test(
     url,
   );
 }
@@ -144,9 +144,12 @@ export class URL {
       } else if (typeof base === 'object') {
         baseUrl = base.toString();
       }
-      if (baseUrl.endsWith('/') && url.startsWith('/')) {
+      if (baseUrl.endsWith('/')) {
         baseUrl = baseUrl.slice(0, baseUrl.length - 1);
       }
+      if (!url.startsWith('/')) {
+        url = `/${url}`;
+      }
       if (baseUrl.endsWith(url)) {
         url = '';
       }
diff --git a/Libraries/Blob/__tests__/URL-test.js b/Libraries/Blob/__tests__/URL-test.js
index 281649ce782..87b8558049b 100644
--- a/Libraries/Blob/__tests__/URL-test.js
+++ b/Libraries/Blob/__tests__/URL-test.js
@@ -33,5 +33,11 @@ describe('URL', function() {
     expect(h.href).toBe('https://developer.mozilla.org/en-US/docs');
     const i = new URL('http://github.com', 'http://google.com');
     expect(i.href).toBe('http://github.com/');
+    // Support Bare Hosts
+    const j = new URL('home', 'http://localhost');
+    expect(j.href).toBe('http://localhost/home');
+    // Insert / between Base and Path if missing
+    const k = new URL('en-US/docs', 'https://developer.mozilla.org');
+    expect(k.href).toBe('https://developer.mozilla.org/en-US/docs');
   });
 });