diff --git a/packages/e2e-test-utils-playwright/src/request-utils/themes.ts b/packages/e2e-test-utils-playwright/src/request-utils/themes.ts
index bb2fbd89781595..802530d947b0fc 100644
--- a/packages/e2e-test-utils-playwright/src/request-utils/themes.ts
+++ b/packages/e2e-test-utils-playwright/src/request-utils/themes.ts
@@ -4,7 +4,7 @@
 import type { RequestUtils } from './index';
 import { WP_BASE_URL } from '../config';
 
-const THEMES_URL = new URL( '/wp-admin/themes.php', WP_BASE_URL ).href;
+const THEMES_URL = new URL( 'wp-admin/themes.php', WP_BASE_URL ).href;
 
 async function activateTheme(
 	this: RequestUtils,
@@ -12,8 +12,9 @@ async function activateTheme(
 ): Promise< void > {
 	let response = await this.request.get( THEMES_URL );
 	const html = await response.text();
+	const optionalFolder = '([a-z0-9-]+%2F)?';
 	const matchGroup = html.match(
-		`action=activate&amp;stylesheet=${ encodeURIComponent(
+		`action=activate&amp;stylesheet=${ optionalFolder }${ encodeURIComponent(
 			themeSlug
 		) }&amp;_wpnonce=[a-z0-9]+`
 	);