diff --git a/Libraries/LibWeb/WebIDL/OverloadResolution.cpp b/Libraries/LibWeb/WebIDL/OverloadResolution.cpp
index a4d762bdcc1..2362f3c3785 100644
--- a/Libraries/LibWeb/WebIDL/OverloadResolution.cpp
+++ b/Libraries/LibWeb/WebIDL/OverloadResolution.cpp
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2024, Shannon Booth <shannon@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -77,7 +78,7 @@ JS::ThrowCompletionOr<ResolvedOverload> resolve_overload(JS::VM& vm, IDL::Effect
     auto distinguishing_argument_index = -1;
 
     // 7. Initialize method to undefined.
-    Optional<JS::FunctionObject&> method;
+    GC::Ptr<JS::FunctionObject> method;
 
     // 8. If there is more than one entry in S, then set d to be the distinguishing argument index for the entries of S.
     if (overloads.size() > 1)
@@ -253,7 +254,7 @@ JS::ThrowCompletionOr<ResolvedOverload> resolve_overload(JS::VM& vm, IDL::Effect
             overloads.remove_all_other_entries();
         }
 
-        // FIXME: 9. Otherwise: if Type(V) is Object and there is an entry in S that has one of the following types at position i of its type list,
+        // 9. Otherwise: if Type(V) is Object and there is an entry in S that has one of the following types at position i of its type list,
         //    - a sequence type
         //    - a frozen array type
         //    - a nullable version of any of the above types
@@ -264,7 +265,28 @@ JS::ThrowCompletionOr<ResolvedOverload> resolve_overload(JS::VM& vm, IDL::Effect
         //        1. Let method be ? GetMethod(V, @@iterator).
         //    }
         //    method is not undefined, then remove from S all other entries.
+        else if (value.is_object()
+            && has_overload_with_argument_type_or_subtype_matching(overloads, i, [&vm, &method, &value](IDL::Type const& type) {
+                   // - a sequence type
+                   // FIXME: - a frozen array type
+                   // - a nullable version of any of the above types
+                   if (type.name() != "sequence")
+                       return false;
 
+                   // and after performing the following steps,
+                   // {
+                   //     1. Let method be ? GetMethod(V, @@iterator).
+                   // }
+                   // method is not undefined, then remove from S all other entries.
+                   auto maybe_method = value.get_method(vm, vm.well_known_symbol_iterator());
+                   if (maybe_method.is_error() || maybe_method.value() == nullptr)
+                       return false;
+
+                   method = *maybe_method.release_value();
+                   return true;
+               })) {
+            overloads.remove_all_other_entries();
+        }
         // 10. Otherwise: if Type(V) is Object and there is an entry in S that has one of the following types at position i of its type list,
         //     - a callback interface type
         //     - a dictionary type
@@ -375,7 +397,7 @@ JS::ThrowCompletionOr<ResolvedOverload> resolve_overload(JS::VM& vm, IDL::Effect
     auto const& callable = overloads.only_item();
 
     // 14. If i = d and method is not undefined, then
-    if (i == distinguishing_argument_index && method.has_value()) {
+    if (i == distinguishing_argument_index && method) {
         // 1. Let V be args[i].
         auto const& value = vm.argument(i);
 
diff --git a/Tests/LibWeb/Text/expected/wpt-import/webmessaging/Channel_postMessage_clone_port_error.any.txt b/Tests/LibWeb/Text/expected/wpt-import/webmessaging/Channel_postMessage_clone_port_error.any.txt
new file mode 100644
index 00000000000..ba4c49f7f5c
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/webmessaging/Channel_postMessage_clone_port_error.any.txt
@@ -0,0 +1,11 @@
+Summary
+
+Harness status: OK
+
+Rerun
+
+Found 1 tests
+
+1 Pass
+Details
+Result	Test Name	MessagePass	Test Description: Throw a DataCloneError if transfer array in postMessage contains source port.	
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/input/wpt-import/webmessaging/Channel_postMessage_clone_port_error.any.html b/Tests/LibWeb/Text/input/wpt-import/webmessaging/Channel_postMessage_clone_port_error.any.html
new file mode 100644
index 00000000000..cd8a947c744
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/webmessaging/Channel_postMessage_clone_port_error.any.html
@@ -0,0 +1,15 @@
+<!doctype html>
+<meta charset=utf-8>
+<title>postMessage() DataCloneError: cloning source port</title>
+<script>
+self.GLOBAL = {
+  isWindow: function() { return true; },
+  isWorker: function() { return false; },
+  isShadowRealm: function() { return false; },
+};
+</script>
+<script src="../resources/testharness.js"></script>
+<script src="../resources/testharnessreport.js"></script>
+
+<div id=log></div>
+<script src="../webmessaging/Channel_postMessage_clone_port_error.any.js"></script>
diff --git a/Tests/LibWeb/Text/input/wpt-import/webmessaging/Channel_postMessage_clone_port_error.any.js b/Tests/LibWeb/Text/input/wpt-import/webmessaging/Channel_postMessage_clone_port_error.any.js
new file mode 100644
index 00000000000..cbee47270c4
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/webmessaging/Channel_postMessage_clone_port_error.any.js
@@ -0,0 +1,14 @@
+// META: title=postMessage() DataCloneError: cloning source port
+
+    var description = "Test Description: Throw a DataCloneError if transfer array in postMessage contains source port.";
+
+    test(function()
+    {
+        var channel = new MessageChannel();
+        channel.port1.start();
+
+        assert_throws_dom("DATA_CLONE_ERR", function()
+        {
+            channel.port1.postMessage("ports", [channel.port1]);
+        });
+    }, description);