diff --git a/keystoneauth1/discover.py b/keystoneauth1/discover.py
index eb7ebf94..97321a14 100644
--- a/keystoneauth1/discover.py
+++ b/keystoneauth1/discover.py
@@ -473,6 +473,12 @@ def _version_from_url(url):
     url = urllib.parse.urlparse(url)
     for part in reversed(url.path.split('/')):
         try:
+            # All integer project ids can parse as valid versions. In URLs
+            # all known instances of versions start with a v. So check to make
+            # sure the url part starts with 'v', then check that it parses
+            # as a valid version.
+            if part[0] != 'v':
+                continue
             return normalize_version_number(part)
         except Exception:
             pass
diff --git a/keystoneauth1/tests/unit/test_discovery.py b/keystoneauth1/tests/unit/test_discovery.py
index 024efc62..9972eb3d 100644
--- a/keystoneauth1/tests/unit/test_discovery.py
+++ b/keystoneauth1/tests/unit/test_discovery.py
@@ -1257,3 +1257,8 @@ class EndpointDataTests(utils.TestCase):
         self.assertEqual(exp, str(epd))
         # Works with implicit stringification
         self.assertEqual(exp, "%s" % epd)
+
+    def test_project_id_int_fallback(self):
+        bad_url = "https://compute.example.com/v2/123456"
+        epd = discover.EndpointData(catalog_url=bad_url)
+        self.assertEqual((2, 0), epd.api_version)