diff --git a/stdlib/uri/0/common.rbs b/stdlib/uri/0/common.rbs
index a68b31feb..b04a4895a 100644
--- a/stdlib/uri/0/common.rbs
+++ b/stdlib/uri/0/common.rbs
@@ -278,7 +278,7 @@ module URI
   #     URI.join('http://example.com', '/foo/', 'bar')
   #     # => #<URI::HTTP http://example.com/foo/bar>
   #
-  def self.join: (String str, *String strs) -> URI::Generic
+  def self.join: (_ToStr | URI::Generic str, *_ToStr | URI::Generic strs) -> URI::Generic
 
   # <!--
   #   rdoc-file=lib/uri/common.rb
diff --git a/test/stdlib/URI_test.rb b/test/stdlib/URI_test.rb
index 884edeb30..fc2131b08 100644
--- a/test/stdlib/URI_test.rb
+++ b/test/stdlib/URI_test.rb
@@ -84,6 +84,8 @@ def test_join
                      URI, :join, "http://example.com"
     assert_send_type "(String, String) -> URI::Generic",
                      URI, :join, "http://example.com", "foo"
+    assert_send_type "(URI::Generic, URI::Generic) -> URI::Generic",
+                     URI, :join, URI("http://example.com"), URI("foo")
   end
 
   def test_parse