diff --git a/.changeset/young-teeth-draw.md b/.changeset/young-teeth-draw.md
new file mode 100644
index 000000000000..b68aeac582cf
--- /dev/null
+++ b/.changeset/young-teeth-draw.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes `experimental_AstroContainer` output including dev toolbar `data-astro-source-file` and `data-astro-source-loc` attributes when rendering components under Vitest
diff --git a/packages/astro/src/core/compile/compile.ts b/packages/astro/src/core/compile/compile.ts
index 39aba5eb0315..ff1566c6035a 100644
--- a/packages/astro/src/core/compile/compile.ts
+++ b/packages/astro/src/core/compile/compile.ts
@@ -63,8 +63,12 @@ export async function compile({
 			scopedStyleStrategy: astroConfig.scopedStyleStrategy,
 			resultScopedSlot: true,
 			transitionsAnimationURL: 'astro/components/viewtransitions.css',
+			// Source annotations only serve the dev toolbar. Vitest also runs Vite in `serve`,
+			// so skip them in `test` mode to keep rendered markup (e.g. from the Container API)
+			// free of machine-specific paths. See https://github.com/withastro/astro/issues/18162
 			annotateSourceFile:
 				viteConfig.command === 'serve' &&
+				viteConfig.mode !== 'test' &&
 				astroConfig.devToolbar &&
 				astroConfig.devToolbar.enabled &&
 				toolbarEnabled,
diff --git a/packages/astro/test/units/compile/annotate-source-file.test.ts b/packages/astro/test/units/compile/annotate-source-file.test.ts
new file mode 100644
index 000000000000..87fe29be860c
--- /dev/null
+++ b/packages/astro/test/units/compile/annotate-source-file.test.ts
@@ -0,0 +1,36 @@
+import * as assert from 'node:assert/strict';
+import { describe, it } from 'node:test';
+import { pathToFileURL } from 'node:url';
+import { resolveConfig } from 'vite';
+import { compile } from '../../../dist/core/compile/index.js';
+import type { AstroConfig } from '../../../dist/types/public/config.js';
+
+async function compileInMode(mode: string) {
+	const result = await compile({
+		astroConfig: {
+			root: pathToFileURL('/'),
+			experimental: {},
+			devToolbar: { enabled: true },
+		} as AstroConfig,
+		viteConfig: await resolveConfig({ configFile: false, mode }, 'serve'),
+		toolbarEnabled: true,
+		filename: '/src/components/Hello.astro',
+		source: `<button type="submit" id="go">Go</button>`,
+	});
+	return result.code;
+}
+
+describe('astro/src/core/compile', () => {
+	describe('annotateSourceFile', () => {
+		it('adds source annotations in dev', async () => {
+			const code = await compileInMode('development');
+			assert.match(code, /data-astro-source-file=/);
+		});
+
+		it('does not add source annotations in Vitest (test mode)', async () => {
+			const code = await compileInMode('test');
+			assert.doesNotMatch(code, /data-astro-source-file=/);
+			assert.doesNotMatch(code, /data-astro-source-loc=/);
+		});
+	});
+});