diff --git a/source/npm/util.js b/source/npm/util.js
index 02736fcb..4ea325e6 100644
--- a/source/npm/util.js
+++ b/source/npm/util.js
@@ -43,7 +43,16 @@ export const username = async ({externalRegistry}) => {
 	}
 };
 
-export const isExternalRegistry = package_ => typeof package_.publishConfig?.registry === 'string';
+const NPM_DEFAULT_REGISTRIES = new Set([
+	// https://docs.npmjs.com/cli/v10/using-npm/registry
+	'https://registry.npmjs.org',
+	// https://docs.npmjs.com/cli/v10/commands/npm-profile#registry
+	'https://registry.npmjs.org/',
+]);
+export const isExternalRegistry = package_ => {
+	const registry = package_.publishConfig?.registry;
+	return typeof registry === 'string' && !NPM_DEFAULT_REGISTRIES.has(registry);
+};
 
 export const collaborators = async package_ => {
 	const packageName = package_.name;
diff --git a/test/npm/util/is-external-registry.js b/test/npm/util/is-external-registry.js
index c449cc66..6b7bcadb 100644
--- a/test/npm/util/is-external-registry.js
+++ b/test/npm/util/is-external-registry.js
@@ -7,4 +7,6 @@ test('main', t => {
 	t.false(npm.isExternalRegistry({name: 'foo'}));
 	t.false(npm.isExternalRegistry({publishConfig: {registry: true}}));
 	t.false(npm.isExternalRegistry({publishConfig: 'not an object'}));
+	t.false(npm.isExternalRegistry({publishConfig: {registry: 'https://registry.npmjs.org'}}));
+	t.false(npm.isExternalRegistry({publishConfig: {registry: 'https://registry.npmjs.org/'}}));
 });