diff --git a/changelog.md b/changelog.md
index b2a0450..a820d59 100644
--- a/changelog.md
+++ b/changelog.md
@@ -60,6 +60,7 @@
   - Run tests with Node.js v18, v20, v21.
   - Updated `actions/checkout` to v3.
   - Updated `actions/setup-node` to v3.
+- Use the `node:` URL scheme for Node.js builtin module imports.
 - Reorganized the test file structure.
 - In tests, for objects with the property `headers` that as of [`@apollo/client`](https://npm.im/@apollo/client) [v3.7.0](https://github.com/apollographql/apollo-client/releases/tag/v3.7.0) is a null-prototype object, use the assertion `deepEqual` instead of `deepStrictEqual`.
 
diff --git a/createUploadLink.test.mjs b/createUploadLink.test.mjs
index 74d5259..3f92dad 100644
--- a/createUploadLink.test.mjs
+++ b/createUploadLink.test.mjs
@@ -1,9 +1,10 @@
 import "./test/polyfillFile.mjs";
 
+import { deepEqual, deepStrictEqual, strictEqual } from "node:assert";
+
 import { ApolloLink } from "@apollo/client/link/core/ApolloLink.js";
 import { concat } from "@apollo/client/link/core/concat.js";
 import { execute } from "@apollo/client/link/core/execute.js";
-import { deepEqual, deepStrictEqual, strictEqual } from "assert";
 import gql from "graphql-tag";
 import revertableGlobals from "revertable-globals";
 
diff --git a/formDataAppendFile.test.mjs b/formDataAppendFile.test.mjs
index 8595924..bc878c3 100644
--- a/formDataAppendFile.test.mjs
+++ b/formDataAppendFile.test.mjs
@@ -1,6 +1,6 @@
 import "./test/polyfillFile.mjs";
 
-import { strictEqual } from "assert";
+import { strictEqual } from "node:assert";
 
 import formDataAppendFile from "./formDataAppendFile.mjs";
 import assertBundleSize from "./test/assertBundleSize.mjs";
diff --git a/test/assertBundleSize.mjs b/test/assertBundleSize.mjs
index 6d32540..cf35ce2 100644
--- a/test/assertBundleSize.mjs
+++ b/test/assertBundleSize.mjs
@@ -1,7 +1,8 @@
-import { fail } from "assert";
+import { fail } from "node:assert";
+import { fileURLToPath } from "node:url";
+
 import esbuild from "esbuild";
 import { gzipSize } from "gzip-size";
-import { fileURLToPath } from "url";
 
 /**
  * Asserts the minified and gzipped bundle size of a module.
diff --git a/test/createUnexpectedCallError.mjs b/test/createUnexpectedCallError.mjs
index 34e0aef..7fdbb1f 100644
--- a/test/createUnexpectedCallError.mjs
+++ b/test/createUnexpectedCallError.mjs
@@ -1,4 +1,4 @@
-import { AssertionError } from "assert";
+import { AssertionError } from "node:assert";
 
 /**
  * Creates an assertion error that a function was unexpectedly called.
diff --git a/test/polyfillFile.mjs b/test/polyfillFile.mjs
index 09ea552..d300b84 100644
--- a/test/polyfillFile.mjs
+++ b/test/polyfillFile.mjs
@@ -1,4 +1,4 @@
-import { File as NodeFile } from "buffer";
+import { File as NodeFile } from "node:buffer";
 
 // TODO: Delete this polyfill once all supported Node.js versions have the
 // global `File`:
diff --git a/test/timeLimitPromise.mjs b/test/timeLimitPromise.mjs
index 749a423..4155172 100644
--- a/test/timeLimitPromise.mjs
+++ b/test/timeLimitPromise.mjs
@@ -1,4 +1,4 @@
-import { AssertionError } from "assert";
+import { AssertionError } from "node:assert";
 
 /**
  * Time limits a promise. It will reject with an assertion error if it doesn’t