diff --git a/neutron/db/uplink_status_propagation_db.py b/neutron/db/uplink_status_propagation_db.py
index ed7fe0edb71..528fb9b67da 100644
--- a/neutron/db/uplink_status_propagation_db.py
+++ b/neutron/db/uplink_status_propagation_db.py
@@ -28,6 +28,10 @@ class UplinkStatusPropagationMixin(object):
 
     @staticmethod
     def _extend_port_dict(port_res, port_db):
+        # NOTE(ralonsoh): the default value is "True". Ports created before
+        # enabling this extension won't have an associated
+        # "PortUplinkStatusPropagation" register but we assume they have this
+        # flag enabled.
         usp_db = port_db.get(usp.PROPAGATE_UPLINK_STATUS)
         port_res[usp.PROPAGATE_UPLINK_STATUS] = (
-            usp_db.propagate_uplink_status if usp_db else False)
+            usp_db.propagate_uplink_status if usp_db else True)
diff --git a/neutron/tests/unit/plugins/ml2/extensions/test_uplink_status_propagation.py b/neutron/tests/unit/plugins/ml2/extensions/test_uplink_status_propagation.py
index b9fd228ded1..c7964cf62fa 100644
--- a/neutron/tests/unit/plugins/ml2/extensions/test_uplink_status_propagation.py
+++ b/neutron/tests/unit/plugins/ml2/extensions/test_uplink_status_propagation.py
@@ -39,7 +39,7 @@ class UplinkStatusPropagationML2ExtDriverTestCase(
 
             driver = usp.UplinkStatusPropagationExtensionDriver()
             driver.extend_port_dict(session, db_data, response_data)
-            self.assertFalse(response_data['propagate_uplink_status'])
+            self.assertTrue(response_data['propagate_uplink_status'])
 
     def test_show_port_has_propagate_uplink_status(self):
         with self.port(propagate_uplink_status=True) as port:
diff --git a/releasenotes/notes/propagate_uplink_status_enabled_default-df3daba66e79d056.yaml b/releasenotes/notes/propagate_uplink_status_enabled_default-df3daba66e79d056.yaml
new file mode 100644
index 00000000000..264b0995f66
--- /dev/null
+++ b/releasenotes/notes/propagate_uplink_status_enabled_default-df3daba66e79d056.yaml
@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    If ``uplink-status-propagation`` extension is enabled, all existing ports
+    before enabling it will have the flag "propagate_uplink_status" enabled by
+    default. This is aligned with the aim of an administrator that enables
+    this extension. Now only new ports can be created with this flag disabled.