diff --git a/CHANGELOG.md b/CHANGELOG.md
index a2425108780d..4792df3f3195 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,14 +2,15 @@
 
 ### Features
 
-- `[jest-environment-jsdom]` [**BREAKING**] Add default `browser` condtion to `exportConditions` for `jsdom` environment ([#11924](https://github.com/facebook/jest/pull/11924))
+- `[jest-environment-jsdom]` [**BREAKING**] Add default `browser` condition to `exportConditions` for `jsdom` environment ([#11924](https://github.com/facebook/jest/pull/11924))
+- `[jest-environment-jsdom]` [**BREAKING**] Migrate to ESM ([#12340](https://github.com/facebook/jest/pull/12340))
 - `[jest-environment-node]` [**BREAKING**] Add default `node` and `node-addon` conditions to `exportConditions` for `node` environment ([#11924](https://github.com/facebook/jest/pull/11924))
+- `[jest-environment-node]` [**BREAKING**] Migrate to ESM ([#12340](https://github.com/facebook/jest/pull/12340))
 - `[@jest/expect-utils]` New module exporting utils for `expect` ([#12323](https://github.com/facebook/jest/pull/12323))
 
 ### Fixes
 
 - `[jest-phabricator]` [**BREAKING**] Convert to ESM ([#12341](https://github.com/facebook/jest/pull/12341))
-
 ### Chore & Maintenance
 
 - `[*]` [**BREAKING**] Drop support for Node v10 and v15 and target first LTS `16.13.0` ([#12220](https://github.com/facebook/jest/pull/12220))
diff --git a/packages/jest-environment-jsdom/src/__tests__/jsdom_environment.test.ts b/packages/jest-environment-jsdom/src/__tests__/jsdom_environment.test.ts
index f10d330a7168..5bb9238c3cd9 100644
--- a/packages/jest-environment-jsdom/src/__tests__/jsdom_environment.test.ts
+++ b/packages/jest-environment-jsdom/src/__tests__/jsdom_environment.test.ts
@@ -6,7 +6,7 @@
  */
 
 import {makeProjectConfig} from '@jest/test-utils';
-import JSDomEnvironment = require('../');
+import JSDomEnvironment from '../';
 
 describe('JSDomEnvironment', () => {
   it('should configure setTimeout/setInterval to use the browser api', () => {
diff --git a/packages/jest-environment-jsdom/src/index.ts b/packages/jest-environment-jsdom/src/index.ts
index 7f89cbfe45d0..1b8bd723ec90 100644
--- a/packages/jest-environment-jsdom/src/index.ts
+++ b/packages/jest-environment-jsdom/src/index.ts
@@ -22,7 +22,7 @@ type Win = Window &
     };
   };
 
-class JSDOMEnvironment implements JestEnvironment<number> {
+export default class JSDOMEnvironment implements JestEnvironment<number> {
   private dom: JSDOM | null;
   fakeTimers: LegacyFakeTimers<number> | null;
   fakeTimersModern: ModernFakeTimers | null;
@@ -161,4 +161,4 @@ class JSDOMEnvironment implements JestEnvironment<number> {
   }
 }
 
-export = JSDOMEnvironment;
+export const TestEnvironment = JSDOMEnvironment;
diff --git a/packages/jest-environment-node/src/__tests__/node_environment.test.ts b/packages/jest-environment-node/src/__tests__/node_environment.test.ts
index 8f4b8f0b935b..ffe4e7c3e5ba 100644
--- a/packages/jest-environment-node/src/__tests__/node_environment.test.ts
+++ b/packages/jest-environment-node/src/__tests__/node_environment.test.ts
@@ -6,9 +6,7 @@
  */
 
 import {makeProjectConfig} from '@jest/test-utils';
-import NodeEnvironment = require('../');
-
-const isTextEncoderDefined = typeof TextEncoder === 'function';
+import NodeEnvironment from '../';
 
 describe('NodeEnvironment', () => {
   it('uses a copy of the process object', () => {
@@ -39,7 +37,6 @@ describe('NodeEnvironment', () => {
     const timer2 = env1.global.setInterval(() => {}, 0);
 
     [timer1, timer2].forEach(timer => {
-      // @ts-expect-error
       expect(timer.id).not.toBeUndefined();
       expect(typeof timer.ref).toBe('function');
       expect(typeof timer.unref).toBe('function');
@@ -52,9 +49,7 @@ describe('NodeEnvironment', () => {
     expect(env.fakeTimersModern).toBeDefined();
   });
 
-  if (isTextEncoderDefined) {
-    test('TextEncoder references the same global Uint8Array constructor', () => {
-      expect(new TextEncoder().encode('abc')).toBeInstanceOf(Uint8Array);
-    });
-  }
+  test('TextEncoder references the same global Uint8Array constructor', () => {
+    expect(new TextEncoder().encode('abc')).toBeInstanceOf(Uint8Array);
+  });
 });
diff --git a/packages/jest-environment-node/src/index.ts b/packages/jest-environment-node/src/index.ts
index 218997c17e0a..7689502a1ef1 100644
--- a/packages/jest-environment-node/src/index.ts
+++ b/packages/jest-environment-node/src/index.ts
@@ -18,7 +18,7 @@ type Timer = {
   unref: () => Timer;
 };
 
-class NodeEnvironment implements JestEnvironment<Timer> {
+export default class NodeEnvironment implements JestEnvironment<Timer> {
   context: Context | null;
   fakeTimers: LegacyFakeTimers<Timer> | null;
   fakeTimersModern: ModernFakeTimers | null;
@@ -46,22 +46,16 @@ class NodeEnvironment implements JestEnvironment<Timer> {
     global.Uint8Array = Uint8Array;
 
     // URL and URLSearchParams are global in Node >= 10
-    if (typeof URL !== 'undefined' && typeof URLSearchParams !== 'undefined') {
-      global.URL = URL;
-      global.URLSearchParams = URLSearchParams;
-    }
+    global.URL = URL;
+    global.URLSearchParams = URLSearchParams;
+
     // TextDecoder and TextDecoder are global in Node >= 11
-    if (
-      typeof TextEncoder !== 'undefined' &&
-      typeof TextDecoder !== 'undefined'
-    ) {
-      global.TextEncoder = TextEncoder;
-      global.TextDecoder = TextDecoder;
-    }
+    global.TextEncoder = TextEncoder;
+    global.TextDecoder = TextDecoder;
+
     // queueMicrotask is global in Node >= 11
-    if (typeof queueMicrotask !== 'undefined') {
-      global.queueMicrotask = queueMicrotask;
-    }
+    global.queueMicrotask = queueMicrotask;
+
     // AbortController is global in Node >= 15
     if (typeof AbortController !== 'undefined') {
       global.AbortController = AbortController;
@@ -142,4 +136,4 @@ class NodeEnvironment implements JestEnvironment<Timer> {
   }
 }
 
-export = NodeEnvironment;
+export const TestEnvironment = NodeEnvironment;