diff --git a/.changeset/brown-bears-retire-adapters.md b/.changeset/brown-bears-retire-adapters.md
new file mode 100644
index 000000000000..5b03c0f3415d
--- /dev/null
+++ b/.changeset/brown-bears-retire-adapters.md
@@ -0,0 +1,9 @@
+---
+'@sveltejs/adapter-node': patch
+'@sveltejs/adapter-static': patch
+'@sveltejs/adapter-cloudflare': patch
+'@sveltejs/adapter-netlify': patch
+'@sveltejs/adapter-vercel': patch
+---
+
+chore: use `node:fs` instead of deprecated `builder.rimraf` and `builder.mkdirp`
diff --git a/.changeset/brown-bears-retire.md b/.changeset/brown-bears-retire.md
new file mode 100644
index 000000000000..600c035e7b09
--- /dev/null
+++ b/.changeset/brown-bears-retire.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+chore: deprecate `builder.rimraf` and `builder.mkdirp` in favour of `node:fs` methods
diff --git a/.changeset/package-fs-helpers.md b/.changeset/package-fs-helpers.md
new file mode 100644
index 000000000000..5b2e03cd03c1
--- /dev/null
+++ b/.changeset/package-fs-helpers.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/package': patch
+---
+
+chore: replace private fs helpers with Node built-ins
diff --git a/packages/adapter-cloudflare/index.js b/packages/adapter-cloudflare/index.js
index c39f57e61521..185c964ceafc 100644
--- a/packages/adapter-cloudflare/index.js
+++ b/packages/adapter-cloudflare/index.js
@@ -1,4 +1,4 @@
-import { copyFileSync, existsSync, readFileSync, writeFileSync } from 'node:fs';
+import { copyFileSync, existsSync, mkdirSync, readFileSync, rmSync, writeFileSync } from 'node:fs';
 import path from 'node:path';
 import process from 'node:process';
 import { fileURLToPath } from 'node:url';
@@ -72,15 +72,15 @@ export default function (options = {}) {
 			const files = fileURLToPath(new URL('./files', import.meta.url).href);
 			const tmp = builder.getBuildDirectory('cloudflare-tmp');
 
-			builder.rimraf(dest);
-			builder.rimraf(worker_dest);
+			rmSync(dest, { force: true, recursive: true });
+			rmSync(worker_dest, { force: true, recursive: true });
 
-			builder.mkdirp(dest);
-			builder.mkdirp(tmp);
+			mkdirSync(dest, { recursive: true });
+			mkdirSync(tmp, { recursive: true });
 
 			// client assets and prerendered pages
 			const assets_dest = `${dest}${builder.config.kit.paths.base}`;
-			builder.mkdirp(assets_dest);
+			mkdirSync(assets_dest, { recursive: true });
 			if (
 				building_for_cloudflare_pages ||
 				wrangler_config.assets?.not_found_handling === '404-page'
diff --git a/packages/adapter-netlify/index.js b/packages/adapter-netlify/index.js
index 2c1355b42425..8e893a94a7a0 100644
--- a/packages/adapter-netlify/index.js
+++ b/packages/adapter-netlify/index.js
@@ -1,4 +1,4 @@
-import { existsSync, readdirSync, readFileSync, writeFileSync } from 'node:fs';
+import { existsSync, mkdirSync, readdirSync, readFileSync, rmSync, writeFileSync } from 'node:fs';
 import { join, posix } from 'node:path';
 import { fileURLToPath } from 'node:url';
 import { builtinModules } from 'node:module';
@@ -60,19 +60,19 @@ export default function ({ split = false, edge = edge_set_in_env_var } = {}) {
 			const publish = get_publish_directory(netlify_config, builder) || 'build';
 
 			// empty out existing build directories
-			builder.rimraf(publish);
-			builder.rimraf('.netlify/v1');
+			rmSync(publish, { force: true, recursive: true });
+			rmSync('.netlify/v1', { force: true, recursive: true });
 
 			// clean up legacy directories from older adapter versions to avoid
 			// gnarly edge cases when an existing project is upgraded to this version
-			builder.rimraf('.netlify/edge-functions');
-			builder.rimraf('.netlify/server');
-			builder.rimraf('.netlify/package.json');
-			builder.rimraf('.netlify/serverless.js');
+			rmSync('.netlify/edge-functions', { force: true, recursive: true });
+			rmSync('.netlify/server', { force: true, recursive: true });
+			rmSync('.netlify/package.json', { force: true, recursive: true });
+			rmSync('.netlify/serverless.js', { force: true, recursive: true });
 			if (existsSync('.netlify/functions-internal')) {
 				for (const file of readdirSync('.netlify/functions-internal')) {
 					if (file.startsWith(FUNCTION_PREFIX)) {
-						builder.rimraf(join('.netlify/functions-internal', file));
+						rmSync(join('.netlify/functions-internal', file), { force: true, recursive: true });
 					}
 				}
 			}
@@ -118,7 +118,7 @@ export default function ({ split = false, edge = edge_set_in_env_var } = {}) {
  */
 function generate_serverless_functions({ builder, publish, split }) {
 	// https://docs.netlify.com/build/frameworks/frameworks-api/#netlifyv1functions
-	builder.mkdirp(netlify_framework_serverless_path);
+	mkdirSync(netlify_framework_serverless_path, { recursive: true });
 
 	builder.writeServer('.netlify/v1/server');
 
@@ -243,7 +243,7 @@ function write_frameworks_config({ builder }) {
 		]
 	};
 
-	builder.mkdirp('.netlify/v1');
+	mkdirSync('.netlify/v1', { recursive: true });
 	writeFileSync(netlify_framework_config_path, s(config));
 }
 
@@ -354,11 +354,11 @@ const rolldown_config = {
  */
 async function generate_edge_functions({ builder }) {
 	const tmp = builder.getBuildDirectory('netlify-tmp');
-	builder.rimraf(tmp);
-	builder.mkdirp(tmp);
+	rmSync(tmp, { force: true, recursive: true });
+	mkdirSync(tmp, { recursive: true });
 
 	// https://docs.netlify.com/build/frameworks/frameworks-api/#edge-functions
-	builder.mkdirp('.netlify/v1/edge-functions');
+	mkdirSync('.netlify/v1/edge-functions', { recursive: true });
 
 	builder.log.minor('Generating Edge Function...');
 	const relativePath = posix.relative(tmp, builder.getServerDirectory());
diff --git a/packages/adapter-node/index.js b/packages/adapter-node/index.js
index dd26779b9380..62fb04a64e5a 100644
--- a/packages/adapter-node/index.js
+++ b/packages/adapter-node/index.js
@@ -1,4 +1,4 @@
-import { readFileSync, writeFileSync } from 'node:fs';
+import { mkdirSync, readFileSync, rmSync, writeFileSync } from 'node:fs';
 import { extname } from 'node:path';
 import { fileURLToPath } from 'node:url';
 import { rolldown } from 'rolldown';
@@ -19,9 +19,9 @@ export default function (opts = {}) {
 		async adapt(builder) {
 			const tmp = builder.getBuildDirectory('adapter-node');
 
-			builder.rimraf(out);
-			builder.rimraf(tmp);
-			builder.mkdirp(tmp);
+			rmSync(out, { force: true, recursive: true });
+			rmSync(tmp, { force: true, recursive: true });
+			mkdirSync(tmp, { recursive: true });
 
 			builder.log.minor('Copying assets');
 			const written = [
diff --git a/packages/adapter-static/index.js b/packages/adapter-static/index.js
index a1d65f277019..f6c0b5a450c4 100644
--- a/packages/adapter-static/index.js
+++ b/packages/adapter-static/index.js
@@ -1,3 +1,4 @@
+import { rmSync } from 'node:fs';
 import path from 'node:path';
 import { platforms } from './platforms.js';
 
@@ -72,8 +73,8 @@ ${dynamic_routes.map((route) => `  - ${path.posix.join(prefix, route.id)}`).join
 				precompress
 			} = options ?? platform?.defaults ?? /** @type {import('./index.js').AdapterOptions} */ ({});
 
-			builder.rimraf(assets);
-			builder.rimraf(pages);
+			rmSync(assets, { force: true, recursive: true });
+			rmSync(pages, { force: true, recursive: true });
 
 			builder.generateEnvModule();
 			builder.writeClient(assets);
diff --git a/packages/adapter-vercel/index.js b/packages/adapter-vercel/index.js
index 13875c7e8187..4f1590665282 100644
--- a/packages/adapter-vercel/index.js
+++ b/packages/adapter-vercel/index.js
@@ -22,8 +22,8 @@ const plugin = function (defaults = {}) {
 			const dir = '.vercel/output';
 			const tmp = builder.getBuildDirectory('vercel-tmp');
 
-			builder.rimraf(dir);
-			builder.rimraf(tmp);
+			fs.rmSync(dir, { force: true, recursive: true });
+			fs.rmSync(tmp, { force: true, recursive: true });
 
 			if (fs.existsSync('vercel.json')) {
 				const vercel_file = fs.readFileSync('vercel.json', 'utf-8');
@@ -215,7 +215,7 @@ const plugin = function (defaults = {}) {
 				const target = path.join(dirs.functions, INTERNAL, 'catchall.func');
 
 				// Ensure the parent directory exists before symlinking
-				builder.mkdirp(path.join(dirs.functions, app_path));
+				fs.mkdirSync(path.join(dirs.functions, app_path), { recursive: true });
 
 				const relative = path.relative(path.dirname(remote_symlink_path), target);
 
@@ -238,7 +238,7 @@ const plugin = function (defaults = {}) {
 				if (isr) {
 					const isr_name = route.id.slice(1) || '__root__'; // should we check that __root__ isn't a route?
 					const base = `${dirs.functions}/${isr_name}`;
-					builder.mkdirp(base);
+					fs.mkdirSync(base, { recursive: true });
 
 					const target = `${dirs.functions}/${name}.func`;
 					const relative = path.relative(path.dirname(base), target);
@@ -289,7 +289,7 @@ const plugin = function (defaults = {}) {
 					const target = path.join(dirs.functions, `${name}.func`); // The actual function directory e.g., .vercel/output/functions/![-].func
 
 					// Ensure the directory for the data endpoint symlink exists (e.g., functions/index/)
-					builder.mkdirp(base_dir);
+					fs.mkdirSync(base_dir, { recursive: true });
 
 					// Calculate relative paths FROM the directory containing the symlink TO the target
 					const relative_for_main = path.relative(path.dirname(main_symlink_path), target);
diff --git a/packages/kit/src/core/adapt/builder.js b/packages/kit/src/core/adapt/builder.js
index 29acc4c30780..4d0f42254cee 100644
--- a/packages/kit/src/core/adapt/builder.js
+++ b/packages/kit/src/core/adapt/builder.js
@@ -5,12 +5,19 @@
 /** @import { RouteData, ValidatedConfig, BuildData, ServerMetadata, ServerMetadataRoute, Prerendered, PrerenderMap, Logger, RemoteChunk } from 'types' */
 import { loadEnv } from 'vite';
 import * as devalue from 'devalue';
-import { createReadStream, createWriteStream, existsSync, statSync } from 'node:fs';
+import {
+	createReadStream,
+	createWriteStream,
+	existsSync,
+	mkdirSync,
+	rmSync,
+	statSync
+} from 'node:fs';
 import { extname, resolve, join, dirname, relative } from 'node:path';
 import { pipeline } from 'node:stream';
 import { promisify } from 'node:util';
 import zlib from 'node:zlib';
-import { copy, rimraf, mkdirp } from '../../utils/filesystem.js';
+import { copy } from '../../utils/filesystem.js';
 import { posixify } from '../../utils/os.js';
 import { generate_manifest } from '../generate_manifest/index.js';
 import { get_route_segments } from '../../utils/routing.js';
@@ -99,8 +106,8 @@ export function create_builder({
 
 	return {
 		log,
-		rimraf,
-		mkdirp,
+		rimraf: (dir) => rmSync(dir, { force: true, recursive: true }),
+		mkdirp: (dir) => mkdirSync(dir, { recursive: true }),
 		copy,
 
 		config,
@@ -271,7 +278,7 @@ export function create_builder({
 							exports: module.exports
 						});
 
-			rimraf(entrypoint);
+			rmSync(entrypoint, { force: true, recursive: true });
 			write(entrypoint, facade);
 		}
 	};
diff --git a/packages/kit/src/core/postbuild/prerender.js b/packages/kit/src/core/postbuild/prerender.js
index ef66691fdda5..34f6ea765db1 100644
--- a/packages/kit/src/core/postbuild/prerender.js
+++ b/packages/kit/src/core/postbuild/prerender.js
@@ -1,7 +1,7 @@
-import { existsSync, readFileSync, statSync, writeFileSync } from 'node:fs';
+import { existsSync, mkdirSync, readFileSync, statSync, writeFileSync } from 'node:fs';
 import { dirname, join } from 'node:path';
 import { pathToFileURL } from 'node:url';
-import { mkdirp, walk } from '../../utils/filesystem.js';
+import { walk } from '../../utils/filesystem.js';
 import { posixify } from '../../utils/os.js';
 import { noop } from '../../utils/functions.js';
 import { decode_uri, is_root_relative, resolve } from '../../utils/url.js';
@@ -157,7 +157,7 @@ async function prerender({ hash, out, manifest_path, metadata, verbose, env, vit
 		const file = output_filename('/', true);
 		const dest = `${config.outDir}/output/prerendered/pages/${file}`;
 
-		mkdirp(dirname(dest));
+		mkdirSync(dirname(dest), { recursive: true });
 		writeFileSync(dest, fallback);
 
 		prerendered.pages.set('/', { file });
@@ -476,7 +476,7 @@ async function prerender({ hash, out, manifest_path, metadata, verbose, env, vit
 				}
 
 				if (!headers['x-sveltekit-normalize']) {
-					mkdirp(dirname(dest));
+					mkdirSync(dirname(dest), { recursive: true });
 
 					writeFileSync(
 						dest,
@@ -522,7 +522,7 @@ async function prerender({ hash, out, manifest_path, metadata, verbose, env, vit
 				);
 			}
 
-			mkdirp(dir);
+			mkdirSync(dir, { recursive: true });
 
 			writeFileSync(dest, body);
 			written.add(file);
diff --git a/packages/kit/src/core/sync/utils.js b/packages/kit/src/core/sync/utils.js
index 9da5d4e282bb..41e26e818ade 100644
--- a/packages/kit/src/core/sync/utils.js
+++ b/packages/kit/src/core/sync/utils.js
@@ -1,7 +1,7 @@
 import fs from 'node:fs';
 import path from 'node:path';
 import { styleText } from 'node:util';
-import { mkdirp, resolve_entry } from '../../utils/filesystem.js';
+import { resolve_entry } from '../../utils/filesystem.js';
 
 /** @type {Map<string, string>} */
 const previous_contents = new Map();
@@ -22,7 +22,7 @@ export function write_if_changed(file, code) {
  */
 export function write(file, code) {
 	previous_contents.set(file, code);
-	mkdirp(path.dirname(file));
+	fs.mkdirSync(path.dirname(file), { recursive: true });
 	fs.writeFileSync(file, code);
 }
 
diff --git a/packages/kit/src/core/sync/write_types/index.js b/packages/kit/src/core/sync/write_types/index.js
index 09d02365e13a..40589df2ab67 100644
--- a/packages/kit/src/core/sync/write_types/index.js
+++ b/packages/kit/src/core/sync/write_types/index.js
@@ -1,7 +1,7 @@
 import fs from 'node:fs';
 import path from 'node:path';
 import MagicString from 'magic-string';
-import { rimraf, walk, resolve_entry } from '../../../utils/filesystem.js';
+import { walk, resolve_entry } from '../../../utils/filesystem.js';
 import { compact } from '../../../utils/array.js';
 import { posixify } from '../../../utils/os.js';
 import { ts } from '../ts.js';
@@ -49,7 +49,7 @@ export function write_all_types(config, manifest_data, root) {
 		for (const file of walk(types_dir)) {
 			const dir = path.dirname(file);
 			if (!expected_directories.has(dir)) {
-				rimraf(path.join(types_dir, file));
+				fs.rmSync(path.join(types_dir, file), { force: true, recursive: true });
 			}
 		}
 	}
diff --git a/packages/kit/src/core/sync/write_types/index.spec.js b/packages/kit/src/core/sync/write_types/index.spec.js
index cc6e369de4ba..4bad115fabe7 100644
--- a/packages/kit/src/core/sync/write_types/index.spec.js
+++ b/packages/kit/src/core/sync/write_types/index.spec.js
@@ -3,7 +3,6 @@ import fs from 'node:fs';
 import path from 'node:path';
 import process from 'node:process';
 import { assert, describe, expect, test } from 'vitest';
-import { rimraf } from '../../../utils/filesystem.js';
 import create_manifest_data from '../create_manifest_data/index.js';
 import { tweak_types, write_all_types } from './index.js';
 import { write_app_types } from '../write_app_types.js';
@@ -16,7 +15,7 @@ const cwd = path.join(import.meta.dirname, 'test');
  * @param {string} dir
  */
 function run_test(dir) {
-	rimraf(path.join(cwd, dir, '.svelte-kit'));
+	fs.rmSync(path.join(cwd, dir, '.svelte-kit'), { force: true, recursive: true });
 
 	const initial = validate_config({});
 
diff --git a/packages/kit/src/exports/public.d.ts b/packages/kit/src/exports/public.d.ts
index 70ce0c084097..209844c2dedc 100644
--- a/packages/kit/src/exports/public.d.ts
+++ b/packages/kit/src/exports/public.d.ts
@@ -121,9 +121,15 @@ type UnpackValidationError<T> =
 export interface Builder {
 	/** Print messages to the console. `log.info` and `log.minor` are silent unless Vite's `logLevel` is `info`. */
 	log: Logger;
-	/** Remove `dir` and all its contents. */
+	/**
+	 * Remove `dir` and all its contents.
+	 * @deprecated Use `fs.rmSync(dir, { force: true, recursive: true })` instead
+	 */
 	rimraf: (dir: string) => void;
-	/** Create `dir` and any required parent directories. */
+	/**
+	 * Create `dir` and any required parent directories.
+	 * @deprecated Use `fs.mkdirSync(dir, { recursive: true })` instead
+	 */
 	mkdirp: (dir: string) => void;
 
 	/** The fully resolved SvelteKit config. */
diff --git a/packages/kit/src/exports/vite/build/build_server.js b/packages/kit/src/exports/vite/build/build_server.js
index de55700d5cb5..1de30641c14c 100644
--- a/packages/kit/src/exports/vite/build/build_server.js
+++ b/packages/kit/src/exports/vite/build/build_server.js
@@ -1,7 +1,6 @@
 /** @import { AssetDependencies, ManifestData, SSRNode, ValidatedKitConfig } from 'types' */
 /** @import { Manifest, Rolldown } from 'vite' */
 import fs from 'node:fs';
-import { mkdirp } from '../../../utils/filesystem.js';
 import {
 	create_function_as_string,
 	filter_fonts,
@@ -36,8 +35,8 @@ export function build_server_nodes(
 	chunks,
 	root
 ) {
-	mkdirp(`${out}/server/nodes`);
-	mkdirp(`${out}/server/stylesheets`);
+	fs.mkdirSync(`${out}/server/nodes`, { recursive: true });
+	fs.mkdirSync(`${out}/server/stylesheets`, { recursive: true });
 
 	/**
 	 * Stylesheet names and their contents which are below the inline threshold
diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index 655843db6996..61a743427bbe 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -11,7 +11,7 @@ import MagicString from 'magic-string';
 import { loadEnv } from 'vite';
 import { exactRegex, prefixRegex } from 'rolldown/filter';
 
-import { copy, mkdirp, read, resolve_entry, rimraf } from '../../utils/filesystem.js';
+import { copy, read, resolve_entry } from '../../utils/filesystem.js';
 import { posixify } from '../../utils/os.js';
 import { to_fs } from '../../utils/vite.js';
 import {
@@ -1551,9 +1551,9 @@ function kit({ svelte_config }) {
 		async buildApp(builder) {
 			// clears the output directories
 			if (!builder.config.build.watch) {
-				rimraf(out);
+				fs.rmSync(out, { force: true, recursive: true });
 			}
-			mkdirp(out);
+			fs.mkdirSync(out, { recursive: true });
 
 			await load_and_validate_params({
 				routes: manifest_data.routes,
diff --git a/packages/kit/src/utils/filesystem.js b/packages/kit/src/utils/filesystem.js
index 1173086bd112..c672f42328c0 100644
--- a/packages/kit/src/utils/filesystem.js
+++ b/packages/kit/src/utils/filesystem.js
@@ -2,28 +2,6 @@ import fs from 'node:fs';
 import path from 'node:path';
 import { posixify } from './os.js';
 
-/** @param {string} dir */
-export function mkdirp(dir) {
-	try {
-		fs.mkdirSync(dir, { recursive: true });
-	} catch (/** @type {any} */ e) {
-		if (e.code === 'EEXIST') {
-			if (!fs.statSync(dir).isDirectory()) {
-				throw new Error(`Cannot create directory ${dir}, a file already exists at this position`, {
-					cause: e
-				});
-			}
-			return;
-		}
-		throw e;
-	}
-}
-
-/** @param {string} path */
-export function rimraf(path) {
-	fs.rmSync(path, { force: true, recursive: true });
-}
-
 /**
  * @param {string} source
  * @param {string} target
@@ -58,7 +36,7 @@ export function copy(source, target, opts = {}) {
 				go(path.join(from, file), path.join(to, file));
 			});
 		} else {
-			mkdirp(path.dirname(to));
+			fs.mkdirSync(path.dirname(to), { recursive: true });
 
 			if (opts.replace) {
 				const data = fs.readFileSync(from, 'utf-8');
diff --git a/packages/kit/src/utils/filesystem.spec.js b/packages/kit/src/utils/filesystem.spec.js
index 86e0322f02ff..29412768d0ed 100644
--- a/packages/kit/src/utils/filesystem.spec.js
+++ b/packages/kit/src/utils/filesystem.spec.js
@@ -2,7 +2,7 @@ import { mkdtempSync, writeFileSync, readdirSync, mkdirSync, readFileSync } from
 import { tmpdir } from 'node:os';
 import { dirname, join } from 'node:path';
 import { assert, expect, beforeEach, test } from 'vitest';
-import { copy, mkdirp, resolve_entry } from './filesystem.js';
+import { copy, resolve_entry } from './filesystem.js';
 
 /** @type {string} */
 let source_dir;
@@ -23,7 +23,7 @@ beforeEach(() => {
  */
 const write = (file, contents) => {
 	const filepath = join(source_dir, file);
-	mkdirp(dirname(filepath));
+	mkdirSync(dirname(filepath), { recursive: true });
 	writeFileSync(filepath, contents);
 };
 
diff --git a/packages/kit/types/index.d.ts b/packages/kit/types/index.d.ts
index 00cc2aac3d70..6f42c0a0130f 100644
--- a/packages/kit/types/index.d.ts
+++ b/packages/kit/types/index.d.ts
@@ -95,9 +95,15 @@ declare module '@sveltejs/kit' {
 	export interface Builder {
 		/** Print messages to the console. `log.info` and `log.minor` are silent unless Vite's `logLevel` is `info`. */
 		log: Logger;
-		/** Remove `dir` and all its contents. */
+		/**
+		 * Remove `dir` and all its contents.
+		 * @deprecated Use `fs.rmSync(dir, { force: true, recursive: true })` instead
+		 */
 		rimraf: (dir: string) => void;
-		/** Create `dir` and any required parent directories. */
+		/**
+		 * Create `dir` and any required parent directories.
+		 * @deprecated Use `fs.mkdirSync(dir, { recursive: true })` instead
+		 */
 		mkdirp: (dir: string) => void;
 
 		/** The fully resolved SvelteKit config. */
diff --git a/packages/package/src/filesystem.js b/packages/package/src/filesystem.js
index 0a0b737728ac..52ee66f8a21b 100644
--- a/packages/package/src/filesystem.js
+++ b/packages/package/src/filesystem.js
@@ -1,108 +1,4 @@
-import fs from 'node:fs';
-import path from 'node:path';
-
-/** @param {string} dir */
-export function mkdirp(dir) {
-	try {
-		fs.mkdirSync(dir, { recursive: true });
-	} catch (/** @type {any} */ e) {
-		if (e.code === 'EEXIST') return;
-		throw e;
-	}
-}
-
-/** @param {string} path */
-export function rimraf(path) {
-	fs.rmSync(path, { force: true, recursive: true });
-}
-
 /** @param {string} str */
 export function posixify(str) {
 	return str.replace(/\\/g, '/');
 }
-
-/**
- * Get a list of all files in a directory
- * @param {string} cwd - the directory to walk
- * @param {boolean} [dirs] - whether to include directories in the result
- */
-export function walk(cwd, dirs = false) {
-	/** @type {string[]} */
-	const all_files = [];
-
-	/** @param {string} dir */
-	function walk_dir(dir) {
-		const files = fs.readdirSync(path.join(cwd, dir));
-
-		for (const file of files) {
-			const joined = path.join(dir, file);
-			const stats = fs.statSync(path.join(cwd, joined));
-			if (stats.isDirectory()) {
-				if (dirs) all_files.push(joined);
-				walk_dir(joined);
-			} else {
-				all_files.push(joined);
-			}
-		}
-	}
-
-	return (walk_dir(''), all_files);
-}
-
-/**
- * @param {string} source
- * @param {string} target
- * @param {{
- *   filter?: (basename: string) => boolean;
- *   replace?: Record<string, string>;
- * }} opts
- */
-export function copy(source, target, opts = {}) {
-	if (!fs.existsSync(source)) return [];
-
-	/** @type {string[]} */
-	const files = [];
-
-	const prefix = posixify(target) + '/';
-
-	const regex = opts.replace
-		? new RegExp(`\\b(${Object.keys(opts.replace).join('|')})\\b`, 'g')
-		: null;
-
-	/**
-	 * @param {string} from
-	 * @param {string} to
-	 */
-	function go(from, to) {
-		if (opts.filter && !opts.filter(path.basename(from))) return;
-
-		const stats = fs.statSync(from);
-
-		if (stats.isDirectory()) {
-			fs.readdirSync(from).forEach((file) => {
-				go(path.join(from, file), path.join(to, file));
-			});
-		} else {
-			mkdirp(path.dirname(to));
-
-			if (opts.replace) {
-				const data = fs.readFileSync(from, 'utf-8');
-				fs.writeFileSync(
-					to,
-					data.replace(
-						/** @type {RegExp} */ (regex),
-						(_match, key) => /** @type {Record<string, string>} */ (opts.replace)[key]
-					)
-				);
-			} else {
-				fs.copyFileSync(from, to);
-			}
-
-			files.push(to === target ? posixify(path.basename(to)) : posixify(to).replace(prefix, ''));
-		}
-	}
-
-	go(source, target);
-
-	return files;
-}
diff --git a/packages/package/src/index.js b/packages/package/src/index.js
index 337cabc18cf3..ef979bdedeb9 100644
--- a/packages/package/src/index.js
+++ b/packages/package/src/index.js
@@ -3,7 +3,7 @@ import * as path from 'node:path';
 import { styleText } from 'node:util';
 import chokidar from 'chokidar';
 import { preprocess } from 'svelte/compiler';
-import { copy, mkdirp, posixify, rimraf } from './filesystem.js';
+import { posixify } from './filesystem.js';
 import {
 	analyze,
 	resolve_aliases,
@@ -35,8 +35,8 @@ async function do_build(options, analyse_code) {
 		throw new Error(`${path.relative('.', input)} does not exist`);
 	}
 
-	rimraf(temp);
-	mkdirp(temp);
+	fs.rmSync(temp, { force: true, recursive: true });
+	fs.mkdirSync(temp, { recursive: true });
 
 	const files = scan(input, extensions);
 
@@ -61,11 +61,11 @@ async function do_build(options, analyse_code) {
 	}
 
 	if (!options.preserve_output) {
-		rimraf(output);
+		fs.rmSync(output, { force: true, recursive: true });
 	}
 
-	mkdirp(output);
-	copy(temp, output);
+	fs.mkdirSync(output, { recursive: true });
+	fs.cpSync(temp, output, { recursive: true, dereference: true });
 
 	console.log(
 		styleText(
@@ -326,7 +326,9 @@ async function process_file(
 
 		analyse_code(file.name, contents);
 		write(dest, contents);
-	} else {
-		copy(filename, dest);
+	} else if (fs.existsSync(filename)) {
+		// copyFileSync rather than cpSync: cpSync with dereference errors on symlinked sources
+		fs.mkdirSync(path.dirname(dest), { recursive: true });
+		fs.copyFileSync(filename, dest);
 	}
 }
diff --git a/packages/package/src/typescript.js b/packages/package/src/typescript.js
index c2de52159acc..61f15c151713 100644
--- a/packages/package/src/typescript.js
+++ b/packages/package/src/typescript.js
@@ -2,7 +2,7 @@ import * as fs from 'node:fs';
 import * as path from 'node:path';
 import { createRequire } from 'node:module';
 import semver from 'semver';
-import { posixify, mkdirp, rimraf, walk } from './filesystem.js';
+import { posixify } from './filesystem.js';
 import { resolve_aliases, write } from './utils.js';
 import { emitDts } from 'svelte2tsx';
 import { load_pkg_json } from './config.js';
@@ -22,8 +22,8 @@ import { load_pkg_json } from './config.js';
  */
 export async function emit_dts(input, output, final_output, cwd, alias, files, tsconfig) {
 	const tmp = `${output}/__package_types_tmp__`;
-	rimraf(tmp);
-	mkdirp(tmp);
+	fs.rmSync(tmp, { force: true, recursive: true });
+	fs.mkdirSync(tmp, { recursive: true });
 
 	const require = createRequire(import.meta.url);
 	const pkg = load_pkg_json(cwd);
@@ -53,8 +53,12 @@ export async function emit_dts(input, output, final_output, cwd, alias, files, t
 		}
 	}
 
+	const generated = fs
+		.readdirSync(tmp, { encoding: 'utf-8', recursive: true })
+		.filter((file) => fs.statSync(path.join(tmp, file)).isFile());
+
 	// resolve $lib alias (TODO others), copy into package dir
-	for (const file of walk(tmp)) {
+	for (const file of generated) {
 		const normalized = posixify(file);
 
 		if (handwritten.has(normalized)) {
@@ -85,7 +89,7 @@ export async function emit_dts(input, output, final_output, cwd, alias, files, t
 		write(path.join(output, normalized), source);
 	}
 
-	rimraf(tmp);
+	fs.rmSync(tmp, { force: true, recursive: true });
 }
 
 /**
diff --git a/packages/package/src/utils.js b/packages/package/src/utils.js
index bdf3f92e82f4..2f75a83b00bb 100644
--- a/packages/package/src/utils.js
+++ b/packages/package/src/utils.js
@@ -1,7 +1,7 @@
 import * as fs from 'node:fs';
 import * as path from 'node:path';
 import { VERSION } from 'svelte/compiler';
-import { posixify, mkdirp, walk } from './filesystem.js';
+import { posixify } from './filesystem.js';
 
 const is_svelte_5_plus = Number(VERSION.split('.')[0]) >= 5;
 
@@ -132,7 +132,7 @@ export function strip_lang_tags(content) {
  * @param {Parameters<typeof fs.writeFileSync>[1]} contents
  */
 export function write(file, contents) {
-	mkdirp(path.dirname(file));
+	fs.mkdirSync(path.dirname(file), { recursive: true });
 	fs.writeFileSync(file, contents);
 }
 
@@ -142,7 +142,10 @@ export function write(file, contents) {
  * @returns {import('./types.js').File[]}
  */
 export function scan(input, extensions) {
-	return walk(input).map((file) => analyze(file, extensions));
+	return fs
+		.readdirSync(input, { encoding: 'utf-8', recursive: true })
+		.filter((file) => fs.statSync(path.join(input, file)).isFile())
+		.map((file) => analyze(file, extensions));
 }
 
 /**
diff --git a/packages/package/test/index.spec.js b/packages/package/test/index.spec.js
index 6ee504171a08..f9629c9124c9 100644
--- a/packages/package/test/index.spec.js
+++ b/packages/package/test/index.spec.js
@@ -7,7 +7,6 @@ import { test, expect } from 'vitest';
 
 import { build, watch } from '../src/index.js';
 import { load_config } from '../src/config.js';
-import { rimraf, walk } from '../src/filesystem.js';
 import { _create_validator } from '../src/validate.js';
 import { resolve_aliases } from '../src/utils.js';
 
@@ -38,8 +37,8 @@ async function test_make_package(path, options) {
 		...options
 	});
 
-	const expected_files = walk(ewd, true);
-	const actual_files = walk(output, true);
+	const expected_files = fs.readdirSync(ewd, { encoding: 'utf-8', recursive: true }).sort();
+	const actual_files = fs.readdirSync(output, { encoding: 'utf-8', recursive: true }).sort();
 
 	expect(actual_files).toEqual(expected_files);
 
@@ -118,7 +117,7 @@ for (const dir of fs.readdirSync(join(import.meta.dirname, 'errors'))) {
 					throw new Error('All error test must be handled', { cause: error });
 			}
 		} finally {
-			rimraf(output);
+			fs.rmSync(output, { force: true, recursive: true });
 		}
 	});
 }
@@ -534,7 +533,7 @@ test('does not warn about server files that import a .ts file which imports $app
 
 test('create package with preserved output', async () => {
 	const output = join(import.meta.dirname, 'fixtures', 'preserve-output', 'dist');
-	rimraf(output);
+	fs.rmSync(output, { force: true, recursive: true });
 	fs.mkdirSync(join(output, 'assets'), { recursive: true });
 	fs.writeFileSync(join(output, 'assets', 'theme.css'), ':root { color: red }');
 	await test_make_package('preserve-output', { preserve_output: true });