diff --git a/.changeset/selfish-lamps-joke.md b/.changeset/selfish-lamps-joke.md
new file mode 100644
index 000000000000..b2003ab2f1b7
--- /dev/null
+++ b/.changeset/selfish-lamps-joke.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/adapter-auto': major
+---
+
+feat: update Vercel, Cloudflare Pages, and Netlify adapter major versions
diff --git a/packages/adapter-auto/adapters.js b/packages/adapter-auto/adapters.js
index edf9e3436e20..0c45dcaec3ae 100644
--- a/packages/adapter-auto/adapters.js
+++ b/packages/adapter-auto/adapters.js
@@ -7,19 +7,19 @@ export const adapters = [
 		name: 'Vercel',
 		test: () => !!process.env.VERCEL,
 		module: '@sveltejs/adapter-vercel',
-		version: '4'
+		version: '5'
 	},
 	{
 		name: 'Cloudflare Pages',
 		test: () => !!process.env.CF_PAGES,
 		module: '@sveltejs/adapter-cloudflare',
-		version: '3'
+		version: '4'
 	},
 	{
 		name: 'Netlify',
 		test: () => !!process.env.NETLIFY,
 		module: '@sveltejs/adapter-netlify',
-		version: '3'
+		version: '4'
 	},
 	{
 		name: 'Azure Static Web Apps',
diff --git a/packages/adapter-auto/package.json b/packages/adapter-auto/package.json
index ef4fbc3ba707..e58aa5697640 100644
--- a/packages/adapter-auto/package.json
+++ b/packages/adapter-auto/package.json
@@ -36,13 +36,15 @@
 	"scripts": {
 		"lint": "prettier --check .",
 		"format": "pnpm lint --write",
-		"check": "tsc"
+		"check": "tsc",
+		"test": "vitest run"
 	},
 	"devDependencies": {
 		"@sveltejs/kit": "workspace:^",
 		"@sveltejs/vite-plugin-svelte": "^5.0.1",
 		"@types/node": "^18.19.48",
-		"typescript": "^5.3.3"
+		"typescript": "^5.3.3",
+		"vitest": "^2.1.6"
 	},
 	"dependencies": {
 		"import-meta-resolve": "^4.1.0"
diff --git a/packages/adapter-auto/test/adapters.spec.js b/packages/adapter-auto/test/adapters.spec.js
new file mode 100644
index 000000000000..abb873fa6a78
--- /dev/null
+++ b/packages/adapter-auto/test/adapters.spec.js
@@ -0,0 +1,16 @@
+import { assert, test } from 'vitest';
+import { adapters } from 'adapters.js';
+import { existsSync, readFileSync } from 'node:fs';
+
+test('adapter versions are up to date', () => {
+	for (const adapter of adapters) {
+		const dir = adapter.module.replace('@sveltejs/', '');
+		const package_json = `../${dir}/package.json`;
+		if (!existsSync(package_json)) {
+			continue;
+		}
+		const adapter_version = JSON.parse(readFileSync(package_json, 'utf-8')).version;
+		const [major] = adapter_version.split('.');
+		assert.equal(adapter.version, major, `${adapter.name} adapter is outdated`);
+	}
+});
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 873ed72ba864..5bba65421e5f 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -51,6 +51,9 @@ importers:
       typescript:
         specifier: ^5.3.3
         version: 5.6.3
+      vitest:
+        specifier: ^2.1.6
+        version: 2.1.6(@types/node@18.19.50)(lightningcss@1.24.1)
 
   packages/adapter-cloudflare:
     dependencies: