diff --git a/lib/fetch/headers.js b/lib/fetch/headers.js
index bfc0b62f169..f37c5c99e03 100644
--- a/lib/fetch/headers.js
+++ b/lib/fetch/headers.js
@@ -471,6 +471,12 @@ class Headers {
   keys () {
     webidl.brandCheck(this, Headers)
 
+    if (this[kGuard] === 'immutable') {
+      const value = this[kHeadersSortedMap]
+      return makeIterator(() => value, 'Headers',
+        'key')
+    }
+
     return makeIterator(
       () => [...this[kHeadersSortedMap].values()],
       'Headers',
@@ -481,6 +487,12 @@ class Headers {
   values () {
     webidl.brandCheck(this, Headers)
 
+    if (this[kGuard] === 'immutable') {
+      const value = this[kHeadersSortedMap]
+      return makeIterator(() => value, 'Headers',
+        'value')
+    }
+
     return makeIterator(
       () => [...this[kHeadersSortedMap].values()],
       'Headers',
@@ -491,6 +503,12 @@ class Headers {
   entries () {
     webidl.brandCheck(this, Headers)
 
+    if (this[kGuard] === 'immutable') {
+      const value = this[kHeadersSortedMap]
+      return makeIterator(() => value, 'Headers',
+        'key+value')
+    }
+
     return makeIterator(
       () => [...this[kHeadersSortedMap].values()],
       'Headers',