diff --git a/.changeset/dull-flowers-prove.md b/.changeset/dull-flowers-prove.md
new file mode 100644
index 000000000000..8a0e05299ac4
--- /dev/null
+++ b/.changeset/dull-flowers-prove.md
@@ -0,0 +1,5 @@
+---
+'@astrojs/netlify': patch
+---
+
+Fix route validation failures on Netlify Edge
diff --git a/packages/integrations/netlify/src/integration-edge-functions.ts b/packages/integrations/netlify/src/integration-edge-functions.ts
index 72ab6fb19b2c..11a18beb9e70 100644
--- a/packages/integrations/netlify/src/integration-edge-functions.ts
+++ b/packages/integrations/netlify/src/integration-edge-functions.ts
@@ -53,7 +53,10 @@ async function createEdgeManifest(routes: RouteData[], entryFile: string, dir: U
 		} else {
 			functions.push({
 				function: entryFile,
-				pattern: route.pattern.toString(),
+				// Make route pattern serializable to match expected
+				// Netlify Edge validation format. Mirrors Netlify's own edge bundler:
+				// https://github.com/netlify/edge-bundler/blob/main/src/manifest.ts#L34
+				pattern: route.pattern.source.replace(/\\\//g, '/').toString(),
 			});
 		}
 	}