diff --git a/.changeset/bright-suns-brake.md b/.changeset/bright-suns-brake.md
new file mode 100644
index 000000000..13660de30
--- /dev/null
+++ b/.changeset/bright-suns-brake.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Preserve pathnames for sitemap.xml
diff --git a/packages/astro/src/core/ssr/sitemap.ts b/packages/astro/src/core/ssr/sitemap.ts
index fd39098e7..e392dd368 100644
--- a/packages/astro/src/core/ssr/sitemap.ts
+++ b/packages/astro/src/core/ssr/sitemap.ts
@@ -6,7 +6,7 @@ export function generateSitemap(pages: string[]): string {
 
 	// copy just in case original copy is needed
 	// make sure that 404 page is excluded
-	const urls = [...pages].filter((url) => !url.endsWith('/404/index.html'));
+	const urls = [...pages].filter((url) => !/404\/?$/.test(url));
 	urls.sort((a, b) => a.localeCompare(b, 'en', { numeric: true })); // sort alphabetically so sitemap is same each time
 	let sitemap = `<?xml version="1.0" encoding="UTF-8"?><urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">`;
 	for (const url of urls) {
diff --git a/packages/astro/src/vite-plugin-build-html/index.ts b/packages/astro/src/vite-plugin-build-html/index.ts
index acb2c87cf..22bad8073 100644
--- a/packages/astro/src/vite-plugin-build-html/index.ts
+++ b/packages/astro/src/vite-plugin-build-html/index.ts
@@ -80,8 +80,7 @@ export function rollupPluginAstroBuildHTML(options: PluginOptions): VitePlugin {
 				}
 
 				for (const pathname of pageData.paths) {
-					const pathrepl = astroConfig.buildOptions.pageUrlFormat === 'directory' ? '/index.html' : pathname === '/' ? 'index.html' : '.html';
-					pageNames.push(pathname.replace(/\/?$/, pathrepl).replace(/^\//, ''));
+					pageNames.push(pathname.replace(/\/?$/, '/').replace(/^\//, ''));
 					const id = ASTRO_PAGE_PREFIX + pathname;
 					const html = await ssrRender(renderers, mod, {
 						astroConfig,
diff --git a/packages/astro/test/astro-sitemap-rss.test.js b/packages/astro/test/astro-sitemap-rss.test.js
index f193ed77b..ca9f8d0db 100644
--- a/packages/astro/test/astro-sitemap-rss.test.js
+++ b/packages/astro/test/astro-sitemap-rss.test.js
@@ -29,7 +29,7 @@ describe('Sitemaps', () => {
 		it('Generates Sitemap correctly', async () => {
 			let sitemap = await fixture.readFile('/sitemap.xml');
 			expect(sitemap).to.equal(
-				`<?xml version="1.0" encoding="UTF-8"?><urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><url><loc>https://astro.build/episode/fazers/index.html</loc></url><url><loc>https://astro.build/episode/rap-snitch-knishes/index.html</loc></url><url><loc>https://astro.build/episode/rhymes-like-dimes/index.html</loc></url><url><loc>https://astro.build/episodes/index.html</loc></url></urlset>\n`
+				`<?xml version="1.0" encoding="UTF-8"?><urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><url><loc>https://astro.build/episode/fazers/</loc></url><url><loc>https://astro.build/episode/rap-snitch-knishes/</loc></url><url><loc>https://astro.build/episode/rhymes-like-dimes/</loc></url><url><loc>https://astro.build/episodes/</loc></url></urlset>\n`
 			);
 		});
 	});