diff --git a/django/urls/converters.py b/django/urls/converters.py
index b36cde1497..d44588174e 100644
--- a/django/urls/converters.py
+++ b/django/urls/converters.py
@@ -1,8 +1,5 @@
 import functools
 import uuid
-import warnings
-
-from django.utils.deprecation import RemovedInDjango60Warning
 
 
 class IntConverter:
@@ -57,14 +54,7 @@ REGISTERED_CONVERTERS = {}
 
 def register_converter(converter, type_name):
     if type_name in REGISTERED_CONVERTERS or type_name in DEFAULT_CONVERTERS:
-        # RemovedInDjango60Warning: when the deprecation ends, replace with
-        # raise ValueError(f"Converter {type_name} is already registered.")
-        warnings.warn(
-            f"Converter {type_name!r} is already registered. Support for overriding "
-            "registered converters is deprecated and will be removed in Django 6.0.",
-            RemovedInDjango60Warning,
-            stacklevel=2,
-        )
+        raise ValueError(f"Converter {type_name!r} is already registered.")
     REGISTERED_CONVERTERS[type_name] = converter()
     get_converters.cache_clear()
 
diff --git a/docs/ref/urls.txt b/docs/ref/urls.txt
index 95eb03f35a..ac55bde575 100644
--- a/docs/ref/urls.txt
+++ b/docs/ref/urls.txt
@@ -150,10 +150,6 @@ The ``converter`` argument is a converter class, and ``type_name`` is the
 converter name to use in path patterns. See
 :ref:`registering-custom-path-converters` for an example.
 
-.. deprecated:: 5.1
-
-    Overriding existing converters is deprecated.
-
 ==================================================
 ``django.conf.urls`` functions for use in URLconfs
 ==================================================
diff --git a/docs/releases/6.0.txt b/docs/releases/6.0.txt
index 5a58dcf599..d8db925fd1 100644
--- a/docs/releases/6.0.txt
+++ b/docs/releases/6.0.txt
@@ -271,4 +271,5 @@ to remove usage of these features.
 See :ref:`deprecated-features-5.1` for details on these changes, including how
 to remove usage of these features.
 
-* ...
+* ``django.urls.register_converter()`` no longer allows overriding existing
+  converters.
diff --git a/docs/topics/http/urls.txt b/docs/topics/http/urls.txt
index 8e57732725..d8de9635ec 100644
--- a/docs/topics/http/urls.txt
+++ b/docs/topics/http/urls.txt
@@ -183,11 +183,6 @@ Register custom converter classes in your URLconf using
         ...,
     ]
 
-.. deprecated:: 5.1
-
-    Overriding existing converters with ``django.urls.register_converter()`` is
-    deprecated.
-
 Using regular expressions
 =========================
 
diff --git a/tests/urlpatterns/tests.py b/tests/urlpatterns/tests.py
index 6c8d6470c0..5f1a45ba1f 100644
--- a/tests/urlpatterns/tests.py
+++ b/tests/urlpatterns/tests.py
@@ -13,8 +13,7 @@ from django.urls import (
     resolve,
     reverse,
 )
-from django.urls.converters import REGISTERED_CONVERTERS, IntConverter
-from django.utils.deprecation import RemovedInDjango60Warning
+from django.urls.converters import IntConverter
 from django.views import View
 
 from .converters import Base64Converter, DynamicConverter
@@ -204,35 +203,14 @@ class SimplifiedURLTests(SimpleTestCase):
             path("foo/<nonexistent:var>/", empty_view)
 
     def test_warning_override_default_converter(self):
-        # RemovedInDjango60Warning: when the deprecation ends, replace with
-        # msg = "Converter 'int' is already registered."
-        # with self.assertRaisesMessage(ValueError, msg):
-        msg = (
-            "Converter 'int' is already registered. Support for overriding registered "
-            "converters is deprecated and will be removed in Django 6.0."
-        )
-        try:
-            with self.assertWarnsMessage(RemovedInDjango60Warning, msg) as ctx:
-                register_converter(IntConverter, "int")
-        finally:
-            REGISTERED_CONVERTERS.pop("int", None)
-        self.assertEqual(ctx.filename, __file__)
+        msg = "Converter 'int' is already registered."
+        with self.assertRaisesMessage(ValueError, msg):
+            register_converter(IntConverter, "int")
 
     def test_warning_override_converter(self):
-        # RemovedInDjango60Warning: when the deprecation ends, replace with
-        # msg = "Converter 'base64' is already registered."
-        # with self.assertRaisesMessage(ValueError, msg):
-        msg = (
-            "Converter 'base64' is already registered. Support for overriding "
-            "registered converters is deprecated and will be removed in Django 6.0."
-        )
-        try:
-            with self.assertWarnsMessage(RemovedInDjango60Warning, msg) as ctx:
-                register_converter(Base64Converter, "base64")
-                register_converter(Base64Converter, "base64")
-        finally:
-            REGISTERED_CONVERTERS.pop("base64", None)
-        self.assertEqual(ctx.filename, __file__)
+        msg = "Converter 'base64' is already registered."
+        with self.assertRaisesMessage(ValueError, msg):
+            register_converter(Base64Converter, "base64")
 
     def test_invalid_view(self):
         msg = "view must be a callable or a list/tuple in the case of include()."