diff --git a/s3fs/core.py b/s3fs/core.py
index d5a55697..12d7057f 100644
--- a/s3fs/core.py
+++ b/s3fs/core.py
@@ -1929,6 +1929,13 @@ async def _invalidate_region_cache(self):
 
     invalidate_region_cache = sync_wrapper(_invalidate_region_cache)
 
+    @property
+    def fsid(self):
+        """Persistent filesystem id that can be used to compare filesystems
+        across sessions.
+        """
+        return "s3"
+
 
 class S3File(AbstractBufferedFile):
     """
diff --git a/s3fs/tests/test_s3fs.py b/s3fs/tests/test_s3fs.py
index 8fe2af5a..f91b9ff8 100644
--- a/s3fs/tests/test_s3fs.py
+++ b/s3fs/tests/test_s3fs.py
@@ -2574,3 +2574,7 @@ def test_cp_two_files(s3):
         target + "/file0",
         target + "/file1",
     ]
+
+
+def test_fsid(s3):
+    assert s3.fsid == "s3"