diff --git a/Libraries/Core/setUpReactDevTools.js b/Libraries/Core/setUpReactDevTools.js
index 46955da62035f5..be647e33b4d2ca 100644
--- a/Libraries/Core/setUpReactDevTools.js
+++ b/Libraries/Core/setUpReactDevTools.js
@@ -39,7 +39,10 @@ if (__DEV__) {
       // Get hostname from development server (packager)
       const devServer = getDevServer();
       const host = devServer.bundleLoadedFromServer
-        ? devServer.url.replace(/https?:\/\//, '').split(':')[0]
+        ? devServer.url
+            .replace(/https?:\/\//, '')
+            .replace(/\/$/, '')
+            .split(':')[0]
         : 'localhost';
 
       // Read the optional global variable for backward compatibility.
diff --git a/ReactAndroid/src/main/java/com/facebook/react/devsupport/DevLoadingViewController.java b/ReactAndroid/src/main/java/com/facebook/react/devsupport/DevLoadingViewController.java
index db8ef299fc67e7..fa1554bda002f4 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/devsupport/DevLoadingViewController.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/devsupport/DevLoadingViewController.java
@@ -69,9 +69,9 @@ public void showForUrl(String url) {
       return;
     }
 
+    int port = parsedURL.getPort() != -1 ? parsedURL.getPort() : parsedURL.getDefaultPort();
     showMessage(
-        context.getString(
-            R.string.catalyst_loading_from_url, parsedURL.getHost() + ":" + parsedURL.getPort()));
+        context.getString(R.string.catalyst_loading_from_url, parsedURL.getHost() + ":" + port));
   }
 
   public void showForRemoteJSEnabled() {
diff --git a/ReactAndroid/src/main/java/com/facebook/react/devsupport/DevSupportManagerBase.java b/ReactAndroid/src/main/java/com/facebook/react/devsupport/DevSupportManagerBase.java
index 76977bfb462639..0141e70c3eb69b 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/devsupport/DevSupportManagerBase.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/devsupport/DevSupportManagerBase.java
@@ -703,7 +703,7 @@ private void resetCurrentContext(@Nullable ReactContext reactContext) {
         URL sourceUrl = new URL(getSourceUrl());
         String path = sourceUrl.getPath().substring(1); // strip initial slash in path
         String host = sourceUrl.getHost();
-        int port = sourceUrl.getPort();
+        int port = sourceUrl.getPort() != -1 ? sourceUrl.getPort() : sourceUrl.getDefaultPort();
         mCurrentContext
             .getJSModule(HMRClient.class)
             .setup("android", path, host, port, mDevSettings.isHotModuleReplacementEnabled());