diff --git a/reference/forms/types/url.rst b/reference/forms/types/url.rst
index 5f97fcb89a4..96984b23226 100644
--- a/reference/forms/types/url.rst
+++ b/reference/forms/types/url.rst
@@ -31,6 +31,11 @@ If a value is submitted that doesn't begin with some protocol (e.g. ``http://``,
 ``ftp://``, etc), this protocol will be prepended to the string when
 the data is submitted to the form.
 
+.. deprecated:: 7.1
+
+    Not setting the ``default_protocol`` option is deprecated since Symfony 7.1
+    and will default to ``null`` in Symfony 8.0.
+
 Overridden Options
 ------------------