diff --git a/src/esm/loaders.ts b/src/esm/loaders.ts
index 95db51fff..f80526e62 100644
--- a/src/esm/loaders.ts
+++ b/src/esm/loaders.ts
@@ -39,7 +39,7 @@ type resolve = (
 
 export const initialize: InitializeHook = async (data) => {
 	if (!data) {
-		throw new Error('tsx must be loaded with --import instead of --loader\nThe --loader flag was deprecated in Node v20.6.0');
+		throw new Error('tsx must be loaded with --import instead of --loader\nThe --loader flag was deprecated in Node v20.6.0 and v18.19.0');
 	}
 };
 
diff --git a/src/utils/node-features.ts b/src/utils/node-features.ts
index fc33e723e..6f456b286 100644
--- a/src/utils/node-features.ts
+++ b/src/utils/node-features.ts
@@ -11,18 +11,21 @@ export const compareNodeVersion = (
 	|| nodeVersion[2] - version[2]
 );
 
-/**
- * Node.js loaders are isolated from v20
- * https://github.com/nodejs/node/issues/49455#issuecomment-1703812193
- * https://github.com/nodejs/node/blob/33710e7e7d39d19449a75911537d630349110a0c/doc/api/module.md#L375-L376
- */
-export const isolatedLoader = compareNodeVersion([20, 0, 0]) >= 0;
-
-export const supportsModuleRegister = compareNodeVersion([20, 6, 0]) >= 0;
+export const supportsModuleRegister = (
+	compareNodeVersion([20, 6, 0]) >= 0
+	|| (
+		compareNodeVersion([20, 0, 0]) < 0
+		&& compareNodeVersion([18, 19, 0]) >= 0
+	)
+);
 
 export const importAttributes = (
 	compareNodeVersion([21, 0, 0]) >= 0
 	|| compareNodeVersion([20, 10, 0]) >= 0
+	|| (
+		compareNodeVersion([20, 0, 0]) < 0
+		&& compareNodeVersion([18, 19, 0]) >= 0
+	)
 );
 
 // Added in v21.0.0
diff --git a/tests/utils/node-versions.ts b/tests/utils/node-versions.ts
index 735c7f0d7..056811918 100644
--- a/tests/utils/node-versions.ts
+++ b/tests/utils/node-versions.ts
@@ -14,7 +14,9 @@ export const nodeVersions = [
 		)
 			? [
 				latestMajor('20.10.0'),
-				latestMajor('18.18.2'),
+				// TODO:
+				// '20.0.0',
+				latestMajor('18.19.0'),
 				'18.0.0',
 			] as const
 			: [] as const
diff --git a/tests/utils/tsx.ts b/tests/utils/tsx.ts
index 35dd8508a..7af361038 100644
--- a/tests/utils/tsx.ts
+++ b/tests/utils/tsx.ts
@@ -44,7 +44,13 @@ export const createNode = async (
 
 	const versionParsed = node.version.split('.').map(Number) as Version;
 	const supports = {
-		moduleRegister: compareNodeVersion([20, 6, 0], versionParsed) >= 0,
+		moduleRegister: (
+			compareNodeVersion([20, 6, 0], versionParsed) >= 0
+			|| (
+				compareNodeVersion([20, 0, 0], versionParsed) < 0
+				&& compareNodeVersion([18, 19, 0], versionParsed) >= 0
+			)
+		),
 
 		// https://nodejs.org/docs/latest-v18.x/api/cli.html#--test
 		cliTestFlag: compareNodeVersion([18, 1, 0], versionParsed) >= 0,