diff --git a/.changeset/fix-dev-port-vite-restart.md b/.changeset/fix-dev-port-vite-restart.md
new file mode 100644
index 000000000000..18990d8de08a
--- /dev/null
+++ b/.changeset/fix-dev-port-vite-restart.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes `--port` flag being ignored after a Vite-triggered server restart (e.g. when a `.env` file changes)
diff --git a/packages/astro/src/core/dev/container.ts b/packages/astro/src/core/dev/container.ts
index 6fbe717d4c3e..e6dcb443416b 100644
--- a/packages/astro/src/core/dev/container.ts
+++ b/packages/astro/src/core/dev/container.ts
@@ -53,7 +53,7 @@ export async function createContainer({
 
 	const {
 		base,
-		server: { host, headers, open: serverOpen, allowedHosts },
+		server: { host, headers, open: serverOpen, allowedHosts, port },
 	} = settings.config;
 
 	// serverOpen = true, isRestart = false
@@ -103,7 +103,7 @@ export async function createContainer({
 	);
 	const viteConfig = await createVite(
 		{
-			server: { host, headers, open, allowedHosts },
+			server: { host, headers, open, allowedHosts, port },
 			optimizeDeps: {
 				include: rendererClientEntries,
 			},