diff --git a/gitlab/v4/objects/groups.py b/gitlab/v4/objects/groups.py
index 453548b94..662ea5d7b 100644
--- a/gitlab/v4/objects/groups.py
+++ b/gitlab/v4/objects/groups.py
@@ -92,7 +92,7 @@ def transfer_project(self, project_id: int, **kwargs: Any) -> None:
             GitlabAuthenticationError: If authentication is not correct
             GitlabTransferProjectError: If the project could not be transferred
         """
-        path = f"/groups/{self.id}/projects/{project_id}"
+        path = f"/groups/{self.encoded_id}/projects/{project_id}"
         self.manager.gitlab.http_post(path, **kwargs)
 
     @cli.register_custom_action("Group", ("scope", "search"))
diff --git a/gitlab/v4/objects/projects.py b/gitlab/v4/objects/projects.py
index 58666ce74..ec0ae391a 100644
--- a/gitlab/v4/objects/projects.py
+++ b/gitlab/v4/objects/projects.py
@@ -441,7 +441,7 @@ def upload(
             with open(filepath, "rb") as f:
                 filedata = f.read()
 
-        url = f"/projects/{self.id}/uploads"
+        url = f"/projects/{self.encoded_id}/uploads"
         file_info = {"file": (filename, filedata)}
         data = self.manager.gitlab.http_post(url, files=file_info)
 
@@ -538,7 +538,7 @@ def transfer_project(self, to_namespace: str, **kwargs: Any) -> None:
             GitlabAuthenticationError: If authentication is not correct
             GitlabTransferProjectError: If the project could not be transferred
         """
-        path = f"/projects/{self.id}/transfer"
+        path = f"/projects/{self.encoded_id}/transfer"
         self.manager.gitlab.http_put(
             path, post_data={"namespace": to_namespace}, **kwargs
         )