diff --git a/metaflow/plugins/datatools/s3/s3.py b/metaflow/plugins/datatools/s3/s3.py
index 2ce11b64763..a758d863ead 100644
--- a/metaflow/plugins/datatools/s3/s3.py
+++ b/metaflow/plugins/datatools/s3/s3.py
@@ -49,6 +49,7 @@
     get_timestamp,
     TRANSIENT_RETRY_START_LINE,
     TRANSIENT_RETRY_LINE_CONTENT,
+    CONSECUTIVE_SLASHES_REGEX,
 )
 
 if TYPE_CHECKING:
@@ -550,7 +551,9 @@ def __init__(
             else:
                 prefix = os.path.join(prefix, run.parent.id, run.id)
 
-            self._s3root = "s3://%s" % os.path.join(bucket, prefix.strip("/"))
+            s3root_raw = "s3://%s" % os.path.join(bucket, prefix.strip("/"))
+            # Normalize the path by collapsing consecutive slashes
+            self._s3root = CONSECUTIVE_SLASHES_REGEX.sub("/", s3root_raw).rstrip("/")
         elif s3root:
             # 2. use an explicit S3 prefix
             parsed = urlparse(to_unicode(s3root))
@@ -558,7 +561,9 @@ def __init__(
                 raise MetaflowS3URLException(
                     "s3root needs to be an S3 URL prefixed with s3://."
                 )
-            self._s3root = s3root.rstrip("/")
+            # Normalize the path by collapsing consecutive slashes
+            normalized = CONSECUTIVE_SLASHES_REGEX.sub("/", s3root)
+            self._s3root = normalized.rstrip("/")
         else:
             # 3. use the client only with full URLs
             self._s3root = None
diff --git a/metaflow/plugins/datatools/s3/s3op.py b/metaflow/plugins/datatools/s3/s3op.py
index 9b0ee45fac1..68a192f8af6 100644
--- a/metaflow/plugins/datatools/s3/s3op.py
+++ b/metaflow/plugins/datatools/s3/s3op.py
@@ -45,6 +45,7 @@
     get_timestamp,
     TRANSIENT_RETRY_LINE_CONTENT,
     TRANSIENT_RETRY_START_LINE,
+    CONSECUTIVE_SLASHES_REGEX,
 )
 import metaflow.tracing as tracing
 from metaflow.metaflow_config import (
@@ -623,7 +624,7 @@ def list_prefix(self, prefix_url, delimiter=""):
                                 and len(key_path) > len(normalized_prefix)
                             ):
                                 continue
-                        url = url_base + key_path
+                        url = CONSECUTIVE_SLASHES_REGEX.sub("/", url_base + key_path)
                         urlobj = S3Url(
                             url=url,
                             bucket=prefix_url.bucket,
@@ -635,7 +636,9 @@ def list_prefix(self, prefix_url, delimiter=""):
                 if "CommonPrefixes" in page:
                     # we get CommonPrefixes if Delimiter is a non-empty string
                     for key in page.get("CommonPrefixes", []):
-                        url = url_base + key["Prefix"]
+                        url = CONSECUTIVE_SLASHES_REGEX.sub(
+                            "/", url_base + key["Prefix"]
+                        )
                         urlobj = S3Url(
                             url=url,
                             bucket=prefix_url.bucket,
diff --git a/metaflow/plugins/datatools/s3/s3util.py b/metaflow/plugins/datatools/s3/s3util.py
index 51a79787653..45304d936f2 100644
--- a/metaflow/plugins/datatools/s3/s3util.py
+++ b/metaflow/plugins/datatools/s3/s3util.py
@@ -1,6 +1,7 @@
 from __future__ import print_function
 from datetime import datetime
 import random
+import re
 import time
 import sys
 import os
@@ -19,6 +20,10 @@
 TRANSIENT_RETRY_LINE_CONTENT = "<none>"
 TRANSIENT_RETRY_START_LINE = "### RETRY INPUTS ###"
 
+# Compiled regex for normalizing consecutive slashes in S3 paths
+# Matches two or more consecutive slashes not preceded by a colon (to preserve s3://)
+CONSECUTIVE_SLASHES_REGEX = re.compile(r"(?<!:)//+")
+
 
 def get_s3_client(s3_role_arn=None, s3_session_vars=None, s3_client_params=None):
     from metaflow.plugins.aws.aws_client import get_aws_client
diff --git a/test/data/s3/test_s3.py b/test/data/s3/test_s3.py
index d6411314112..b7e6a3666fe 100644
--- a/test/data/s3/test_s3.py
+++ b/test/data/s3/test_s3.py
@@ -982,10 +982,13 @@ def test_list_recursive_sibling_prefix_filtering(inject_failure_rate):
     ) as s3:
         objects = s3.list_recursive()
 
+        # Use the normalized s3root from the S3 object for accurate path extraction
+        test_prefix_path = f"{s3_setup._s3root}/{test_prefix}/"
+
         found_relative_paths = []
         for obj in objects:
             # Get path relative to our test prefix
-            relative_path = obj.url.replace(f"{base_s3root}/{test_prefix}/", "")
+            relative_path = obj.url.replace(test_prefix_path, "")
             found_relative_paths.append(relative_path)
 
         expected_under_log = ["log/test.txt"]