diff --git a/AK/URL.cpp b/AK/URL.cpp
index 8a5ee622416..6bc43c4af3f 100644
--- a/AK/URL.cpp
+++ b/AK/URL.cpp
@@ -166,7 +166,7 @@ bool URL::compute_validity() const
 }
 
 // https://url.spec.whatwg.org/#default-port
-u16 URL::default_port_for_scheme(StringView scheme)
+Optional<u16> URL::default_port_for_scheme(StringView scheme)
 {
     // Spec defined mappings with port:
     if (scheme == "ftp")
@@ -188,7 +188,7 @@ u16 URL::default_port_for_scheme(StringView scheme)
     if (scheme == "ircs")
         return 6697;
 
-    return 0;
+    return {};
 }
 
 URL URL::create_with_file_scheme(DeprecatedString const& path, DeprecatedString const& fragment, DeprecatedString const& hostname)
diff --git a/AK/URL.h b/AK/URL.h
index 55ec4e1762c..01221b30048 100644
--- a/AK/URL.h
+++ b/AK/URL.h
@@ -84,7 +84,7 @@ public:
     DeprecatedString path_segment_at_index(size_t index) const;
     size_t path_segment_count() const { return m_paths.size(); }
 
-    u16 port_or_default() const { return m_port.value_or(default_port_for_scheme(m_scheme)); }
+    u16 port_or_default() const { return m_port.value_or(default_port_for_scheme(m_scheme).value_or(0)); }
     bool cannot_be_a_base_url() const { return m_cannot_be_a_base_url; }
     bool cannot_have_a_username_or_password_or_port() const;
 
@@ -131,7 +131,7 @@ public:
     static URL create_with_help_scheme(DeprecatedString const& path, DeprecatedString const& fragment = {}, DeprecatedString const& hostname = {});
     static URL create_with_data(StringView mime_type, StringView payload, bool is_base64 = false);
 
-    static u16 default_port_for_scheme(StringView);
+    static Optional<u16> default_port_for_scheme(StringView);
     static bool is_special_scheme(StringView);
 
     enum class SpaceAsPlus {
diff --git a/Tests/LibWeb/Text/expected/URL/url.txt b/Tests/LibWeb/Text/expected/URL/url.txt
index cad194eaac8..dcb44a8f2e9 100644
--- a/Tests/LibWeb/Text/expected/URL/url.txt
+++ b/Tests/LibWeb/Text/expected/URL/url.txt
@@ -34,3 +34,12 @@ hostname => '[1:1:0:0:1::]'
 port => ''
 pathname => '/'
 search => ''
+unknown://serenityos.org:0
+protocol => 'unknown:'
+username => ''
+password => ''
+host => 'serenityos.org:0'
+hostname => 'serenityos.org'
+port => '0'
+pathname => ''
+search => ''
diff --git a/Tests/LibWeb/Text/input/URL/url.html b/Tests/LibWeb/Text/input/URL/url.html
index 041f775b939..1f17dc77381 100644
--- a/Tests/LibWeb/Text/input/URL/url.html
+++ b/Tests/LibWeb/Text/input/URL/url.html
@@ -19,6 +19,7 @@
             'http://[0:1:0:1:0:1:0:1]',
             'http://[1:0:1:0:1:0:1:0]',
             'http://[1:1:0:0:1:0:0:0]/',
+            'unknown://serenityos.org:0',
         ]) {
             printURL(url);
         }