diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationCheckbox-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationCheckbox-test.js
index 606ec88b8989..178ed7982a44 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationCheckbox-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationCheckbox-test.js
@@ -15,7 +15,7 @@ const ReactDOMServerIntegrationUtils = require('./utils/ReactDOMServerIntegratio
 const {disableInputAttributeSyncing} = require('shared/ReactFeatureFlags');
 
 let React;
-let ReactDOM;
+let ReactDOMClient;
 let ReactDOMServer;
 let ReactTestUtils;
 
@@ -23,13 +23,13 @@ function initModules() {
   // Reset warning cache.
   jest.resetModules();
   React = require('react');
-  ReactDOM = require('react-dom');
+  ReactDOMClient = require('react-dom/client');
   ReactDOMServer = require('react-dom/server');
   ReactTestUtils = require('react-dom/test-utils');
 
   // Make them available to the helpers.
   return {
-    ReactDOM,
+    ReactDOMClient,
     ReactDOMServer,
     ReactTestUtils,
   };
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationClassContextType-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationClassContextType-test.js
index dda475b7ced3..2df2d66b9b9f 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationClassContextType-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationClassContextType-test.js
@@ -13,7 +13,7 @@
 const ReactDOMServerIntegrationUtils = require('./utils/ReactDOMServerIntegrationTestUtils');
 
 let React;
-let ReactDOM;
+let ReactDOMClient;
 let ReactDOMServer;
 let ReactTestUtils;
 
@@ -21,13 +21,13 @@ function initModules() {
   // Reset warning cache.
   jest.resetModules();
   React = require('react');
-  ReactDOM = require('react-dom');
+  ReactDOMClient = require('react-dom/client');
   ReactDOMServer = require('react-dom/server');
   ReactTestUtils = require('react-dom/test-utils');
 
   // Make them available to the helpers.
   return {
-    ReactDOM,
+    ReactDOMClient,
     ReactDOMServer,
     ReactTestUtils,
   };
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationFragment-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationFragment-test.js
index 680f283b6dbf..8e8fc2aa8fe2 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationFragment-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationFragment-test.js
@@ -13,7 +13,7 @@
 const ReactDOMServerIntegrationUtils = require('./utils/ReactDOMServerIntegrationTestUtils');
 
 let React;
-let ReactDOM;
+let ReactDOMClient;
 let ReactDOMServer;
 let ReactTestUtils;
 
@@ -21,13 +21,13 @@ function initModules() {
   // Reset warning cache.
   jest.resetModules();
   React = require('react');
-  ReactDOM = require('react-dom');
+  ReactDOMClient = require('react-dom/client');
   ReactDOMServer = require('react-dom/server');
   ReactTestUtils = require('react-dom/test-utils');
 
   // Make them available to the helpers.
   return {
-    ReactDOM,
+    ReactDOMClient,
     ReactDOMServer,
     ReactTestUtils,
   };
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationInput-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationInput-test.js
index afbbf28a41ec..54780dae52cd 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationInput-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationInput-test.js
@@ -15,7 +15,7 @@ const ReactDOMServerIntegrationUtils = require('./utils/ReactDOMServerIntegratio
 const {disableInputAttributeSyncing} = require('shared/ReactFeatureFlags');
 
 let React;
-let ReactDOM;
+let ReactDOMClient;
 let ReactDOMServer;
 let ReactTestUtils;
 
@@ -23,13 +23,13 @@ function initModules() {
   // Reset warning cache.
   jest.resetModules();
   React = require('react');
-  ReactDOM = require('react-dom');
+  ReactDOMClient = require('react-dom/client');
   ReactDOMServer = require('react-dom/server');
   ReactTestUtils = require('react-dom/test-utils');
 
   // Make them available to the helpers.
   return {
-    ReactDOM,
+    ReactDOMClient,
     ReactDOMServer,
     ReactTestUtils,
   };
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationModes-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationModes-test.js
index e551a72b9ace..99cf33b821f1 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationModes-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationModes-test.js
@@ -13,7 +13,7 @@
 const ReactDOMServerIntegrationUtils = require('./utils/ReactDOMServerIntegrationTestUtils');
 
 let React;
-let ReactDOM;
+let ReactDOMClient;
 let ReactDOMServer;
 let ReactTestUtils;
 
@@ -21,13 +21,13 @@ function initModules() {
   // Reset warning cache.
   jest.resetModules();
   React = require('react');
-  ReactDOM = require('react-dom');
+  ReactDOMClient = require('react-dom/client');
   ReactDOMServer = require('react-dom/server');
   ReactTestUtils = require('react-dom/test-utils');
 
   // Make them available to the helpers.
   return {
-    ReactDOM,
+    ReactDOMClient,
     ReactDOMServer,
     ReactTestUtils,
   };
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationRefs-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationRefs-test.js
index 76da3e92c82a..e5564d3d9348 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationRefs-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationRefs-test.js
@@ -12,7 +12,7 @@
 const ReactDOMServerIntegrationUtils = require('./utils/ReactDOMServerIntegrationTestUtils');
 
 let React;
-let ReactDOM;
+let ReactDOMClient;
 let ReactDOMServer;
 let ReactTestUtils;
 
@@ -20,13 +20,13 @@ function initModules() {
   // Reset warning cache.
   jest.resetModules();
   React = require('react');
-  ReactDOM = require('react-dom');
+  ReactDOMClient = require('react-dom/client');
   ReactDOMServer = require('react-dom/server');
   ReactTestUtils = require('react-dom/test-utils');
 
   // Make them available to the helpers.
   return {
-    ReactDOM,
+    ReactDOMClient,
     ReactDOMServer,
     ReactTestUtils,
   };
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationSpecialTypes-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationSpecialTypes-test.js
index f3a8b869ad81..8ea1c9d53bae 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationSpecialTypes-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationSpecialTypes-test.js
@@ -13,7 +13,7 @@
 const ReactDOMServerIntegrationUtils = require('./utils/ReactDOMServerIntegrationTestUtils');
 
 let React;
-let ReactDOM;
+let ReactDOMClient;
 let ReactDOMServer;
 let ReactTestUtils;
 let forwardRef;
@@ -26,7 +26,7 @@ function initModules() {
   // Reset warning cache.
   jest.resetModules();
   React = require('react');
-  ReactDOM = require('react-dom');
+  ReactDOMClient = require('react-dom/client');
   ReactDOMServer = require('react-dom/server');
   ReactTestUtils = require('react-dom/test-utils');
   forwardRef = React.forwardRef;
@@ -44,7 +44,7 @@ function initModules() {
 
   // Make them available to the helpers.
   return {
-    ReactDOM,
+    ReactDOMClient,
     ReactDOMServer,
     ReactTestUtils,
   };
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationTextarea-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationTextarea-test.js
index 697ec7f340d8..dd19385e62c5 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationTextarea-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationTextarea-test.js
@@ -13,7 +13,7 @@
 const ReactDOMServerIntegrationUtils = require('./utils/ReactDOMServerIntegrationTestUtils');
 
 let React;
-let ReactDOM;
+let ReactDOMClient;
 let ReactDOMServer;
 let ReactTestUtils;
 
@@ -21,13 +21,13 @@ function initModules() {
   // Reset warning cache.
   jest.resetModules();
   React = require('react');
-  ReactDOM = require('react-dom');
+  ReactDOMClient = require('react-dom/client');
   ReactDOMServer = require('react-dom/server');
   ReactTestUtils = require('react-dom/test-utils');
 
   // Make them available to the helpers.
   return {
-    ReactDOM,
+    ReactDOMClient,
     ReactDOMServer,
     ReactTestUtils,
   };
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationUserInteraction-test.js b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationUserInteraction-test.js
index b335b03b01d3..bc5980f23dda 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerIntegrationUserInteraction-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerIntegrationUserInteraction-test.js
@@ -12,7 +12,7 @@
 const ReactDOMServerIntegrationUtils = require('./utils/ReactDOMServerIntegrationTestUtils');
 
 let React;
-let ReactDOM;
+let ReactDOMClient;
 let ReactDOMServer;
 let ReactTestUtils;
 
@@ -20,13 +20,13 @@ function initModules() {
   // Reset warning cache.
   jest.resetModules();
   React = require('react');
-  ReactDOM = require('react-dom');
+  ReactDOMClient = require('react-dom/client');
   ReactDOMServer = require('react-dom/server');
   ReactTestUtils = require('react-dom/test-utils');
 
   // Make them available to the helpers.
   return {
-    ReactDOM,
+    ReactDOMClient,
     ReactDOMServer,
     ReactTestUtils,
   };
diff --git a/packages/react-dom/src/__tests__/ReactDOMserverIntegrationProgress-test.js b/packages/react-dom/src/__tests__/ReactDOMserverIntegrationProgress-test.js
index b949e0ab522f..cf51eff4aced 100644
--- a/packages/react-dom/src/__tests__/ReactDOMserverIntegrationProgress-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMserverIntegrationProgress-test.js
@@ -13,7 +13,7 @@
 const ReactDOMServerIntegrationUtils = require('./utils/ReactDOMServerIntegrationTestUtils');
 
 let React;
-let ReactDOM;
+let ReactDOMClient;
 let ReactDOMServer;
 let ReactTestUtils;
 
@@ -21,13 +21,13 @@ function initModules() {
   // Reset warning cache.
   jest.resetModules();
   React = require('react');
-  ReactDOM = require('react-dom');
+  ReactDOMClient = require('react-dom/client');
   ReactDOMServer = require('react-dom/server');
   ReactTestUtils = require('react-dom/test-utils');
 
   // Make them available to the helpers.
   return {
-    ReactDOM,
+    ReactDOMClient,
     ReactDOMServer,
     ReactTestUtils,
   };
diff --git a/packages/react-dom/src/__tests__/utils/ReactDOMServerIntegrationTestUtils.js b/packages/react-dom/src/__tests__/utils/ReactDOMServerIntegrationTestUtils.js
index 8392b57af03c..f188812f1311 100644
--- a/packages/react-dom/src/__tests__/utils/ReactDOMServerIntegrationTestUtils.js
+++ b/packages/react-dom/src/__tests__/utils/ReactDOMServerIntegrationTestUtils.js
@@ -14,11 +14,12 @@ const shouldIgnoreConsoleError = require('../../../../../scripts/jest/shouldIgno
 
 module.exports = function (initModules) {
   let ReactDOM;
+  let ReactDOMClient;
   let ReactDOMServer;
   let act;
 
   function resetModules() {
-    ({ReactDOM, ReactDOMServer} = initModules());
+    ({ReactDOM, ReactDOMClient, ReactDOMServer} = initModules());
     act = require('internal-test-utils').act;
   }
 
@@ -51,11 +52,20 @@ module.exports = function (initModules) {
   async function asyncReactDOMRender(reactElement, domElement, forceHydrate) {
     if (forceHydrate) {
       await act(() => {
-        ReactDOM.hydrate(reactElement, domElement);
+        if (ReactDOMClient) {
+          ReactDOMClient.hydrateRoot(domElement, reactElement);
+        } else {
+          ReactDOM.hydrate(reactElement, domElement);
+        }
       });
     } else {
       await act(() => {
-        ReactDOM.render(reactElement, domElement);
+        if (ReactDOMClient) {
+          const root = ReactDOMClient.createRoot(domElement);
+          root.render(reactElement);
+        } else {
+          ReactDOM.render(reactElement, domElement);
+        }
       });
     }
   }
@@ -80,7 +90,11 @@ module.exports = function (initModules) {
       for (let i = 0; i < console.error.mock.calls.length; i++) {
         const args = console.error.mock.calls[i];
         const [format, ...rest] = args;
-        if (!shouldIgnoreConsoleError(format, rest)) {
+        if (
+          !shouldIgnoreConsoleError(format, rest, {
+            TODO_ignoreHydrationErrors: true,
+          })
+        ) {
           filteredWarnings.push(args);
         }
       }
diff --git a/scripts/jest/shouldIgnoreConsoleError.js b/scripts/jest/shouldIgnoreConsoleError.js
index 42aae220debe..f922715c5861 100644
--- a/scripts/jest/shouldIgnoreConsoleError.js
+++ b/scripts/jest/shouldIgnoreConsoleError.js
@@ -1,6 +1,10 @@
 'use strict';
 
-module.exports = function shouldIgnoreConsoleError(format, args) {
+module.exports = function shouldIgnoreConsoleError(
+  format,
+  args,
+  {TODO_ignoreHydrationErrors} = {TODO_ignoreHydrationErrors: false}
+) {
   if (__DEV__) {
     if (typeof format === 'string') {
       if (format.indexOf('Error: Uncaught [') === 0) {
@@ -23,6 +27,15 @@ module.exports = function shouldIgnoreConsoleError(format, args) {
         // We haven't finished migrating our tests to use createRoot.
         return true;
       }
+      if (
+        TODO_ignoreHydrationErrors &&
+        format.indexOf('An error occurred during hydration') !== -1
+      ) {
+        // When switching to createRoot, this error isn't accounted for.
+        // Rather than update all tests, we're ignoring it. But we should
+        // updated the tests to account for this error.
+        return true;
+      }
     } else if (
       format != null &&
       typeof format.message === 'string' &&
@@ -34,6 +47,21 @@ module.exports = function shouldIgnoreConsoleError(format, args) {
         // in development that is reported by jest-environment-jsdom. Ignore because it's noisy.
         return true;
       }
+
+      if (
+        (TODO_ignoreHydrationErrors &&
+          format.message.indexOf('Hydration failed because') !== -1) ||
+        format.message.indexOf(
+          'Text content does not match server-rendered HTML'
+        ) !== -1 ||
+        format.message.indexOf('There was an error while hydrating.') !== -1 ||
+        format.message.indexOf('An error occurred during hydration') !== -1
+      ) {
+        // When switching to createRoot, these errors aren't accounted for.
+        // Rather than update all tests, we're ignoring them. But we should
+        // updated the tests to account for these errors.
+        return true;
+      }
     }
   } else {
     if (