diff --git a/src/default-tmp.ts b/src/default-tmp.ts
index ad545174..014509af 100644
--- a/src/default-tmp.ts
+++ b/src/default-tmp.ts
@@ -10,8 +10,8 @@
 // it uses os.tmpdir() always.
 import { tmpdir } from 'os'
 import { parse, resolve } from 'path'
-import { promises, statSync } from './fs'
-import platform from './platform'
+import { promises, statSync } from './fs.js'
+import platform from './platform.js'
 const { stat } = promises
 
 const isDirSync = (path: string) => {
diff --git a/src/fix-eperm.ts b/src/fix-eperm.ts
index d6389775..17372a9e 100644
--- a/src/fix-eperm.ts
+++ b/src/fix-eperm.ts
@@ -1,4 +1,4 @@
-import { promises, chmodSync, FsError } from './fs'
+import { promises, chmodSync, FsError } from './fs.js'
 const { chmod } = promises
 
 export const fixEPERM =
diff --git a/src/ignore-enoent.ts b/src/ignore-enoent.ts
index c2e8c87a..ec1dc770 100644
--- a/src/ignore-enoent.ts
+++ b/src/ignore-enoent.ts
@@ -1,4 +1,4 @@
-import { FsError } from './fs'
+import { FsError } from './fs.js'
 
 export const ignoreENOENT = async (p: Promise<any>) =>
   p.catch(er => {
diff --git a/src/index.ts b/src/index.ts
index 4f4f6e14..c94f4a60 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,5 +1,5 @@
-import optArg from './opt-arg'
-import pathArg from './path-arg'
+import optArg from './opt-arg.js'
+import pathArg from './path-arg.js'
 
 export interface RimrafOptions {
   preserveRoot?: boolean
@@ -35,12 +35,12 @@ export const assertRimrafOptions: (o: any) => void = (
 }
 /* c8 ignore stop */
 
-import { rimrafManual, rimrafManualSync } from './rimraf-manual'
-import { rimrafMoveRemove, rimrafMoveRemoveSync } from './rimraf-move-remove'
-import { rimrafNative, rimrafNativeSync } from './rimraf-native'
-import { rimrafPosix, rimrafPosixSync } from './rimraf-posix'
-import { rimrafWindows, rimrafWindowsSync } from './rimraf-windows'
-import { useNative, useNativeSync } from './use-native'
+import { rimrafManual, rimrafManualSync } from './rimraf-manual.js'
+import { rimrafMoveRemove, rimrafMoveRemoveSync } from './rimraf-move-remove.js'
+import { rimrafNative, rimrafNativeSync } from './rimraf-native.js'
+import { rimrafPosix, rimrafPosixSync } from './rimraf-posix.js'
+import { rimrafWindows, rimrafWindowsSync } from './rimraf-windows.js'
+import { useNative, useNativeSync } from './use-native.js'
 
 const wrap =
   (fn: (p: string, o: RimrafOptions) => Promise<void>) =>
diff --git a/src/opt-arg.ts b/src/opt-arg.ts
index 5c739b5d..f767f1b9 100644
--- a/src/opt-arg.ts
+++ b/src/opt-arg.ts
@@ -1,4 +1,4 @@
-import { assertRimrafOptions, RimrafOptions } from './index'
+import { assertRimrafOptions, RimrafOptions } from './index.js'
 export default (opt: RimrafOptions = {}) => {
   assertRimrafOptions(opt)
   return opt
diff --git a/src/path-arg.ts b/src/path-arg.ts
index a6a36c78..4adaf5e8 100644
--- a/src/path-arg.ts
+++ b/src/path-arg.ts
@@ -1,7 +1,7 @@
-import platform from './platform'
+import platform from './platform.js'
 import { resolve, parse } from 'path'
 import { inspect } from 'util'
-import { RimrafOptions } from './index'
+import { RimrafOptions } from './index.js'
 
 const pathArg = (path: string, opt: RimrafOptions = {}) => {
   const type = typeof path
diff --git a/src/readdir-or-error.ts b/src/readdir-or-error.ts
index ff639694..82dd5315 100644
--- a/src/readdir-or-error.ts
+++ b/src/readdir-or-error.ts
@@ -1,6 +1,6 @@
 // returns an array of entries if readdir() works,
 // or the error that readdir() raised if not.
-import { FsError, promises, readdirSync } from './fs'
+import { FsError, promises, readdirSync } from './fs.js'
 const { readdir } = promises
 export const readdirOrError = (path: string) =>
   readdir(path).catch(er => er as FsError)
diff --git a/src/retry-busy.ts b/src/retry-busy.ts
index 78f27c65..69c4778e 100644
--- a/src/retry-busy.ts
+++ b/src/retry-busy.ts
@@ -1,7 +1,7 @@
 // note: max backoff is the maximum that any *single* backoff will do
 
 import { RimrafOptions } from '.'
-import { FsError } from './fs'
+import { FsError } from './fs.js'
 
 export const MAXBACKOFF = 200
 export const RATE = 1.2
diff --git a/src/rimraf-manual.ts b/src/rimraf-manual.ts
index c377a60a..d943460f 100644
--- a/src/rimraf-manual.ts
+++ b/src/rimraf-manual.ts
@@ -1,7 +1,7 @@
-import platform from './platform'
+import platform from './platform.js'
 
-import { rimrafPosix, rimrafPosixSync } from './rimraf-posix'
-import { rimrafWindows, rimrafWindowsSync } from './rimraf-windows'
+import { rimrafPosix, rimrafPosixSync } from './rimraf-posix.js'
+import { rimrafWindows, rimrafWindowsSync } from './rimraf-windows.js'
 
 export const rimrafManual = platform === 'win32' ? rimrafWindows : rimrafPosix
 export const rimrafManualSync =
diff --git a/src/rimraf-move-remove.ts b/src/rimraf-move-remove.ts
index cbf23556..40068903 100644
--- a/src/rimraf-move-remove.ts
+++ b/src/rimraf-move-remove.ts
@@ -12,9 +12,9 @@
 // However, it is HELLA SLOW, like 2-10x slower than a naive recursive rm.
 
 import { basename, parse, resolve } from 'path'
-import { defaultTmp, defaultTmpSync } from './default-tmp'
+import { defaultTmp, defaultTmpSync } from './default-tmp.js'
 
-import { ignoreENOENT, ignoreENOENTSync } from './ignore-enoent'
+import { ignoreENOENT, ignoreENOENTSync } from './ignore-enoent.js'
 
 import {
   chmodSync,
@@ -27,7 +27,7 @@ import {
 const { rename, unlink, rmdir, chmod } = fsPromises
 
 import { RimrafOptions } from '.'
-import { readdirOrError, readdirOrErrorSync } from './readdir-or-error'
+import { readdirOrError, readdirOrErrorSync } from './readdir-or-error.js'
 
 // crypto.randomBytes is much slower, and Math.random() is enough here
 const uniqueFilename = (path: string) => `.${basename(path)}.${Math.random()}`
diff --git a/src/rimraf-native.ts b/src/rimraf-native.ts
index 74b23243..6c1c0be0 100644
--- a/src/rimraf-native.ts
+++ b/src/rimraf-native.ts
@@ -1,5 +1,5 @@
 import { RimrafOptions } from '.'
-import { promises, rmSync } from './fs'
+import { promises, rmSync } from './fs.js'
 const { rm } = promises
 
 export const rimrafNative = (path: string, opt: RimrafOptions) =>
diff --git a/src/rimraf-posix.ts b/src/rimraf-posix.ts
index 72dedac9..709207f8 100644
--- a/src/rimraf-posix.ts
+++ b/src/rimraf-posix.ts
@@ -5,15 +5,15 @@
 // calls), because sunos will let root unlink a directory, and some
 // SUPER weird breakage happens as a result.
 
-import { promises, rmdirSync, unlinkSync } from './fs'
+import { promises, rmdirSync, unlinkSync } from './fs.js'
 const { rmdir, unlink } = promises
 
 import { parse, resolve } from 'path'
 
-import { readdirOrError, readdirOrErrorSync } from './readdir-or-error'
+import { readdirOrError, readdirOrErrorSync } from './readdir-or-error.js'
 
 import { RimrafOptions } from '.'
-import { ignoreENOENT, ignoreENOENTSync } from './ignore-enoent'
+import { ignoreENOENT, ignoreENOENTSync } from './ignore-enoent.js'
 
 export const rimrafPosix = async (path: string, opt: RimrafOptions) => {
   const entries = await readdirOrError(path)
diff --git a/src/rimraf-windows.ts b/src/rimraf-windows.ts
index 785908c9..57259cea 100644
--- a/src/rimraf-windows.ts
+++ b/src/rimraf-windows.ts
@@ -9,12 +9,12 @@
 // Note: "move then remove" is 2-10 times slower, and just as unreliable.
 
 import { parse, resolve } from 'path'
-import { ignoreENOENT, ignoreENOENTSync } from './ignore-enoent'
-import { fixEPERM, fixEPERMSync } from './fix-eperm'
-import { readdirOrError, readdirOrErrorSync } from './readdir-or-error'
-import { retryBusy, retryBusySync } from './retry-busy'
-import { rimrafMoveRemove, rimrafMoveRemoveSync } from './rimraf-move-remove'
-import { FsError, promises, rmdirSync, unlinkSync } from './fs'
+import { ignoreENOENT, ignoreENOENTSync } from './ignore-enoent.js'
+import { fixEPERM, fixEPERMSync } from './fix-eperm.js'
+import { readdirOrError, readdirOrErrorSync } from './readdir-or-error.js'
+import { retryBusy, retryBusySync } from './retry-busy.js'
+import { rimrafMoveRemove, rimrafMoveRemoveSync } from './rimraf-move-remove.js'
+import { FsError, promises, rmdirSync, unlinkSync } from './fs.js'
 import { RimrafOptions } from '.'
 const { unlink, rmdir } = promises
 
diff --git a/src/use-native.ts b/src/use-native.ts
index d60ed036..97642176 100644
--- a/src/use-native.ts
+++ b/src/use-native.ts
@@ -3,7 +3,7 @@ const versArr = version.replace(/^v/, '').split('.')
 const hasNative = +versArr[0] > 14 || (+versArr[0] === 14 && +versArr[1] >= 14)
 // we do NOT use native by default on Windows, because Node's native
 // rm implementation is less advanced.  Change this code if that changes.
-import platform from './platform'
+import platform from './platform.js'
 export const useNative =
   !hasNative || platform === 'win32' ? () => false : () => true
 export const useNativeSync =
diff --git a/test/fs.ts b/test/fs.ts
index 7e3a7d5c..c74a1a46 100644
--- a/test/fs.ts
+++ b/test/fs.ts
@@ -5,7 +5,7 @@ import t from 'tap'
 // and that when the cb returns an error, the promised version fails,
 // and when the cb returns data, the promisified version resolves to it.
 import realFS from 'fs'
-import * as fs from '../src/fs'
+import * as fs from '../dist/cjs/src/fs.js'
 
 const mockFSMethodPass =
   (method: string) =>
@@ -20,7 +20,7 @@ const mockFSMethodFail =
     process.nextTick(() => cb(new Error('oops'), method, 1, 2, 3))
   }
 
-import { useNative } from '../src/use-native'
+import { useNative } from '../dist/cjs/src/use-native.js'
 t.type(fs.promises, Object)
 const mockFSPass: { [k: string]: (...a: any[]) => any } = {}
 const mockFSFail: { [k: string]: (...a: any[]) => any } = {}