diff --git a/metaflow/plugins/datatools/s3/s3op.py b/metaflow/plugins/datatools/s3/s3op.py
index 2dbea548131..0f642fbe555 100644
--- a/metaflow/plugins/datatools/s3/s3op.py
+++ b/metaflow/plugins/datatools/s3/s3op.py
@@ -582,11 +582,23 @@ def list_prefix(self, prefix_url, delimiter=""):
                 # - the trailing slash is significant in S3
                 if "Contents" in page:
                     for key in page.get("Contents", []):
-                        url = url_base + key["Key"]
+                        key_path = key["Key"]
+                        # filter out sibling directories that share the same prefix
+                        if delimiter == "":  # recursive mode
+                            normalized_prefix = prefix_url.path
+                            if not normalized_prefix.endswith("/"):
+                                normalized_prefix += "/"
+                            # Only include keys that are actually under our directory
+                            if not (
+                                key_path.startswith(normalized_prefix)
+                                and len(key_path) > len(normalized_prefix)
+                            ):
+                                continue
+                        url = url_base + key_path
                         urlobj = S3Url(
                             url=url,
                             bucket=prefix_url.bucket,
-                            path=key["Key"],
+                            path=key_path,
                             local=generate_local_path(url),
                             prefix=prefix_url.url,
                         )
diff --git a/test/data/s3/test_s3.py b/test/data/s3/test_s3.py
index 13512785a82..30f1b7db63e 100644
--- a/test/data/s3/test_s3.py
+++ b/test/data/s3/test_s3.py
@@ -949,3 +949,56 @@ def _files(blobs):
         ) as s3:
             s3objs = s3.get_many(key for key, blob in shuffled_blobs)
             assert {s3obj.key for s3obj in s3objs} == {key for key, _ in shuffled_blobs}
+
+
+@pytest.mark.parametrize("inject_failure_rate", [0, 10, 50, 90])
+def test_list_recursive_sibling_prefix_filtering(inject_failure_rate):
+    test_prefix = f"test_log_filtering_{uuid4().hex[:8]}"
+    base_s3root = s3_data.S3ROOT
+
+    test_files = [
+        f"{test_prefix}/log/test.txt",
+        f"{test_prefix}/log_other/other.txt",
+        f"{test_prefix}/something/other.txt",
+    ]
+
+    with S3(s3root=base_s3root) as s3_setup:
+        for file_path in test_files:
+            s3_setup.put(file_path, f"test content for {file_path}")
+
+    with S3(
+        s3root=f"{base_s3root}/{test_prefix}/log/",
+        inject_failure_rate=inject_failure_rate,
+    ) as s3:
+        objects = s3.list_recursive()
+
+        found_relative_paths = []
+        for obj in objects:
+            # Get path relative to our test prefix
+            relative_path = obj.url.replace(f"{base_s3root}/{test_prefix}/", "")
+            found_relative_paths.append(relative_path)
+
+        expected_under_log = ["log/test.txt"]
+
+        invalid_paths = [
+            path
+            for path in found_relative_paths
+            if path.startswith(("log_other/", "something/"))
+        ]
+
+        assert len(invalid_paths) == 0, (
+            f"list_recursive incorrectly included sibling directories: {invalid_paths}. "
+            f"When listing under 'log/', only files under log/ should be returned."
+        )
+
+        assert set(found_relative_paths) == set(expected_under_log), (
+            f"Expected files under log/: {expected_under_log}, "
+            f"but got: {found_relative_paths}"
+        )
+
+        assert len(objects) == 1, f"Expected 1 object under log/, got {len(objects)}"
+
+        assert objects[0].exists, "Object should exist"
+        assert objects[0].url.endswith(
+            "/log/test.txt"
+        ), f"Expected object to end with '/log/test.txt', got: {objects[0].url}"