diff --git a/.changeset/fix-codespaces-custom-tunnel.md b/.changeset/fix-codespaces-custom-tunnel.md
new file mode 100644
index 00000000000..e1dc11a0df5
--- /dev/null
+++ b/.changeset/fix-codespaces-custom-tunnel.md
@@ -0,0 +1,5 @@
+---
+'@shopify/app': patch
+---
+
+Respect `--tunnel-url` when running `shopify app dev` in GitHub Codespaces.
diff --git a/packages/app/src/cli/services/dev/urls.test.ts b/packages/app/src/cli/services/dev/urls.test.ts
index e21ec3aff65..30b3d6925dc 100644
--- a/packages/app/src/cli/services/dev/urls.test.ts
+++ b/packages/app/src/cli/services/dev/urls.test.ts
@@ -410,6 +410,19 @@ describe('generateFrontendURL', () => {
     expect(got).toEqual({frontendUrl: 'https://my-tunnel-provider.io', frontendPort: 4242, usingLocalhost: false})
   })
 
+  test('returns tunnelUrl when running in a codespace environment', async () => {
+    // Given
+    vi.mocked(codespaceURL).mockReturnValue('codespace.url.fqdn.com')
+    vi.mocked(codespacePortForwardingDomain).mockReturnValue('app.github.dev')
+    const options = {...defaultOptions, tunnelUrl: 'https://my-tunnel-provider.io:4242'}
+
+    // When
+    const got = await generateFrontendURL(options)
+
+    // Then
+    expect(got).toEqual({frontendUrl: 'https://my-tunnel-provider.io', frontendPort: 4242, usingLocalhost: false})
+  })
+
   test('generates a tunnel url with cloudflare when there is no tunnelUrl and use cloudflare is true', async () => {
     // Given
     const options: FrontendURLOptions = {
diff --git a/packages/app/src/cli/services/dev/urls.ts b/packages/app/src/cli/services/dev/urls.ts
index 8db28d4a880..e1b18f7a184 100644
--- a/packages/app/src/cli/services/dev/urls.ts
+++ b/packages/app/src/cli/services/dev/urls.ts
@@ -47,10 +47,10 @@ interface FrontendURLResult {
 
 /**
  * The tunnel creation logic depends on 7 variables:
- * - If a Codespaces environment is detected, then the URL is built using the codespaces hostname. No need for tunnel
- * - If a Gitpod environment is detected, then the URL is built using the gitpod hostname. No need for tunnel
- *   No need for tunnel. In case problems with that configuration, the flags Tunnel or Custom Tunnel url could be used
  * - If a tunnelUrl is provided, that takes preference and is returned as the frontendURL
+ * - If a Codespaces environment is detected, then the URL is built using the codespaces hostname. No need for tunnel
+ * - If a Gitpod environment is detected, then the URL is built using the gitpod hostname.
+ *   In case problems with that configuration, the Custom Tunnel URL flag could be used
  * - If noTunnel is true, that takes second preference and localhost is used
  * - Otherwise, a tunnel is created. (by default using cloudflare)
  *
@@ -69,17 +69,6 @@ export async function generateFrontendURL(options: FrontendURLOptions): Promise<
   let frontendUrl = ''
   const usingLocalhost = options.noTunnelUseLocalhost
 
-  if (codespaceURL()) {
-    frontendUrl = `https://${codespaceURL()}-${frontendPort}.${codespacePortForwardingDomain()}`
-    return {frontendUrl, frontendPort, usingLocalhost}
-  }
-
-  if (gitpodURL()) {
-    const defaultUrl = gitpodURL()?.replace('https://', '')
-    frontendUrl = `https://${frontendPort}-${defaultUrl}`
-    return {frontendUrl, frontendPort, usingLocalhost}
-  }
-
   if (options.tunnelUrl) {
     const matches = options.tunnelUrl.match(/(https:\/\/[^:]+):([0-9]+)/)
     if (!matches) {
@@ -91,6 +80,17 @@ export async function generateFrontendURL(options: FrontendURLOptions): Promise<
     return {frontendUrl, frontendPort, usingLocalhost}
   }
 
+  if (codespaceURL()) {
+    frontendUrl = `https://${codespaceURL()}-${frontendPort}.${codespacePortForwardingDomain()}`
+    return {frontendUrl, frontendPort, usingLocalhost}
+  }
+
+  if (gitpodURL()) {
+    const defaultUrl = gitpodURL()?.replace('https://', '')
+    frontendUrl = `https://${frontendPort}-${defaultUrl}`
+    return {frontendUrl, frontendPort, usingLocalhost}
+  }
+
   if (options.tunnelClient) {
     frontendPort = options.tunnelClient.port
     frontendUrl = await pollTunnelURL(options.tunnelClient)