diff --git a/runtime/js/99_main.js b/runtime/js/99_main.js
index 4c0a9b5e7dfc08..8164e0c9a2c7ae 100644
--- a/runtime/js/99_main.js
+++ b/runtime/js/99_main.js
@@ -667,7 +667,7 @@ ObjectDefineProperties(finalDenoNs, {
         new Error().stack,
         'Use `Symbol.for("Deno.customInspect")` instead.',
       );
-      return customInspect;
+      return internals.future ? undefined : customInspect;
     },
   },
 });
diff --git a/tests/specs/future/runtime_api/main.js b/tests/specs/future/runtime_api/main.js
index 5308bb73aa31ad..a79185e925d9da 100644
--- a/tests/specs/future/runtime_api/main.js
+++ b/tests/specs/future/runtime_api/main.js
@@ -61,8 +61,12 @@ if (Deno.build.os === "windows") {
 // TLS
 // Since these tests may run in parallel, ensure this port is unique to this file
 const tlsPort = 4510;
-const cert = Deno.readTextFileSync("../../../testdata/tls/localhost.crt");
-const key = Deno.readTextFileSync("../../../testdata/tls/localhost.key");
+const cert = Deno.readTextFileSync(
+  new URL("../../../testdata/tls/localhost.crt", import.meta.url),
+);
+const key = Deno.readTextFileSync(
+  new URL("../../../testdata/tls/localhost.key", import.meta.url),
+);
 const tlsListener = Deno.listenTls({ port: tlsPort, cert, key });
 console.log("Deno.TlsListener.prototype.rid is", tlsListener.rid);
 
@@ -88,4 +92,6 @@ try {
   }
 }
 
+console.log("Deno.customInspect is", Deno.customInspect);
+
 self.close();
diff --git a/tests/specs/future/runtime_api/main.out b/tests/specs/future/runtime_api/main.out
index 8ecca657ff1a22..1bc41c026eb19d 100644
--- a/tests/specs/future/runtime_api/main.out
+++ b/tests/specs/future/runtime_api/main.out
@@ -34,3 +34,4 @@ Deno.TlsListener.prototype.rid is undefined
 Deno.TlsConn.prototype.rid is undefined
 Deno.FsWatcher.prototype.rid is undefined
 Deno.FsFile constructor is illegal
+Deno.customInspect is undefined