diff --git a/cli/js/deno.ts b/cli/js/deno.ts
index 38b2f6d2ad..5843d5fbfc 100644
--- a/cli/js/deno.ts
+++ b/cli/js/deno.ts
@@ -59,7 +59,7 @@ export {
 export { metrics, Metrics } from "./ops/runtime.ts";
 export { mkdirSync, mkdir, MkdirOptions } from "./ops/fs/mkdir.ts";
 export { connect, listen, Listener, Conn } from "./net.ts";
-export { dir, env, exit, execPath, hostname } from "./ops/os.ts";
+export { dir, env, exit, execPath } from "./ops/os.ts";
 export { run, RunOptions, Process, ProcessStatus } from "./process.ts";
 export { DirEntry, readDirSync, readDir } from "./ops/fs/read_dir.ts";
 export { readFileSync, readFile } from "./read_file.ts";
diff --git a/cli/js/deno_unstable.ts b/cli/js/deno_unstable.ts
index 57d1a0970f..4d964f3bd4 100644
--- a/cli/js/deno_unstable.ts
+++ b/cli/js/deno_unstable.ts
@@ -5,7 +5,7 @@
 export { umask } from "./ops/fs/umask.ts";
 export { linkSync, link } from "./ops/fs/link.ts";
 export { symlinkSync, symlink } from "./ops/fs/symlink.ts";
-export { dir, loadavg, osRelease } from "./ops/os.ts";
+export { dir, loadavg, osRelease, hostname } from "./ops/os.ts";
 export { openPlugin } from "./ops/plugins.ts";
 export { transpileOnly, compile, bundle } from "./compiler_api.ts";
 export { applySourceMap, formatDiagnostics } from "./ops/errors.ts";
diff --git a/cli/js/lib.deno.ns.d.ts b/cli/js/lib.deno.ns.d.ts
index 1eeb863073..8c91f145e3 100644
--- a/cli/js/lib.deno.ns.d.ts
+++ b/cli/js/lib.deno.ns.d.ts
@@ -97,14 +97,6 @@ declare namespace Deno {
    * */
   export function test(name: string, fn: () => void | Promise<void>): void;
 
-  /** Get the `hostname` of the machine the Deno process is running on.
-   *
-   *       console.log(Deno.hostname());
-   *
-   *  Requires `allow-env` permission.
-   */
-  export function hostname(): string;
-
   /** Exit the Deno process with optional exit code. If no exit code is supplied
    * then Deno will exit with return code of 0.
    *
diff --git a/cli/js/lib.deno.unstable.d.ts b/cli/js/lib.deno.unstable.d.ts
index a523300ccc..10587d3dfb 100644
--- a/cli/js/lib.deno.unstable.d.ts
+++ b/cli/js/lib.deno.unstable.d.ts
@@ -1174,4 +1174,12 @@ declare namespace Deno {
     state: PermissionState;
     constructor(state: PermissionState);
   }
+
+  /** Get the `hostname` of the machine the Deno process is running on.
+   *
+   *       console.log(Deno.hostname());
+   *
+   *  Requires `allow-env` permission.
+   */
+  export function hostname(): string;
 }
diff --git a/cli/ops/os.rs b/cli/ops/os.rs
index d9a6b30958..6c18015207 100644
--- a/cli/ops/os.rs
+++ b/cli/ops/os.rs
@@ -173,6 +173,7 @@ fn op_hostname(
   _args: Value,
   _zero_copy: Option<ZeroCopyBuf>,
 ) -> Result<JsonOp, OpError> {
+  state.check_unstable("Deno.hostname");
   state.check_env()?;
   let hostname = sys_info::hostname().unwrap_or_else(|_| "".to_string());
   Ok(JsonOp::Sync(json!(hostname)))