diff --git a/neutron_vpnaas/db/vpn/vpn_db.py b/neutron_vpnaas/db/vpn/vpn_db.py
index 60df1be8b..53dc16df9 100644
--- a/neutron_vpnaas/db/vpn/vpn_db.py
+++ b/neutron_vpnaas/db/vpn/vpn_db.py
@@ -555,6 +555,29 @@ class VPNPluginDb(vpnaas.VPNPluginBase,
                     subnet_id=subnet_id,
                     vpnservice_id=vpnservices['id'])
 
+            query = context.session.query(vpn_models.IPsecSiteConnection)
+            query = query.join(
+                vpn_models.VPNEndpointGroup,
+                vpn_models.VPNEndpointGroup.id ==
+                vpn_models.IPsecSiteConnection.local_ep_group_id).filter(
+                vpn_models.VPNEndpointGroup.endpoint_type ==
+                v_constants.SUBNET_ENDPOINT)
+            query = query.join(
+                vpn_models.VPNEndpoint,
+                vpn_models.VPNEndpoint.endpoint_group_id ==
+                vpn_models.IPsecSiteConnection.local_ep_group_id).filter(
+                vpn_models.VPNEndpoint.endpoint == subnet_id)
+            query = query.join(
+                vpn_models.VPNService,
+                vpn_models.VPNService.id ==
+                vpn_models.IPsecSiteConnection.vpnservice_id).filter(
+                vpn_models.VPNService.router_id == router_id)
+            connection = query.first()
+            if connection:
+                raise vpnaas.SubnetInUseByIPsecSiteConnection(
+                    subnet_id=subnet_id,
+                    ipsec_site_connection_id=connection['id'])
+
     def check_subnet_in_use_by_endpoint_group(self, context, subnet_id):
         with context.session.begin(subtransactions=True):
             query = context.session.query(vpn_models.VPNEndpointGroup)
diff --git a/neutron_vpnaas/extensions/vpnaas.py b/neutron_vpnaas/extensions/vpnaas.py
index d588822ce..082fb3d5f 100644
--- a/neutron_vpnaas/extensions/vpnaas.py
+++ b/neutron_vpnaas/extensions/vpnaas.py
@@ -78,6 +78,11 @@ class SubnetInUseByEndpointGroup(nexception.InUse):
     message = _("Subnet %(subnet_id)s is used by endpoint group %(group_id)s")
 
 
+class SubnetInUseByIPsecSiteConnection(nexception.InUse):
+    message = _("Subnet %(subnet_id)s is used by ipsec site connection "
+                "%(ipsec_site_connection_id)s")
+
+
 class VPNStateInvalidToUpdate(nexception.BadRequest):
     message = _("Invalid state %(state)s of vpnaas resource %(id)s"
                 " for updating")
diff --git a/neutron_vpnaas/tests/unit/db/vpn/test_vpn_db.py b/neutron_vpnaas/tests/unit/db/vpn/test_vpn_db.py
index a109eb022..d318fa7ac 100644
--- a/neutron_vpnaas/tests/unit/db/vpn/test_vpn_db.py
+++ b/neutron_vpnaas/tests/unit/db/vpn/test_vpn_db.py
@@ -1733,7 +1733,7 @@ class NeutronResourcesMixin(object):
         }}
         return self.core_plugin.create_port(self.context, port)
 
-    def create_basic_topology(self):
+    def create_basic_topology(self, create_router_port=True):
         """Setup networks, subnets, and a router for testing VPN."""
 
         public_net = self.create_network(overrides={'name': 'public',
@@ -1755,7 +1755,8 @@ class NeutronResourcesMixin(object):
                    'subnet_id': public_subnet['id'],
                    'ip': '192.168.100.5'}
         router = self.create_router(gw=gw_info)
-        self.create_router_port_for_subnet(router, private_subnet)
+        if create_router_port:
+            self.create_router_port_for_subnet(router, private_subnet)
         return (private_subnet, router)
 
 
@@ -2203,3 +2204,40 @@ class TestVpnDatabase(base.NeutronDbPluginV2TestCase, NeutronResourcesMixin):
         self.assertRaises(vpnaas.SubnetInUseByEndpointGroup,
                           self.plugin.check_subnet_in_use_by_endpoint_group,
                           self.context, local_subnet['id'])
+
+    def test_subnet_in_use_by_ipsec_site_connection(self):
+        mock.patch.object(self.plugin, '_get_validator').start()
+
+        private_subnet, router = self.create_basic_topology(
+            create_router_port=False)
+        self.l3_plugin.add_router_interface(
+            self.context,
+            router['id'],
+            {'subnet_id': private_subnet['id']})
+        vpn_service_info = self.prepare_service_info(private_subnet=None,
+                                                     router=router)
+        vpn_service = self.plugin.create_vpnservice(self.context,
+                                                    vpn_service_info)
+
+        ike_policy = self.create_ike_policy()
+        ipsec_policy = self.create_ipsec_policy()
+        ipsec_site_connection = self.prepare_connection_info(
+            vpn_service['id'],
+            ike_policy['id'],
+            ipsec_policy['id'])
+
+        local_ep_group = self.create_endpoint_group(
+            group_type='subnet', endpoints=[private_subnet['id']])
+        peer_ep_group = self.create_endpoint_group(
+            group_type='cidr', endpoints=['20.1.0.0/24', '20.2.0.0/24'])
+        ipsec_site_connection['ipsec_site_connection'].update(
+            {'local_ep_group_id': local_ep_group['id'],
+             'peer_ep_group_id': peer_ep_group['id']})
+        self.plugin.create_ipsec_site_connection(self.context,
+                                                 ipsec_site_connection)
+
+        self.assertRaises(vpnaas.SubnetInUseByIPsecSiteConnection,
+                          self.plugin.check_subnet_in_use,
+                          self.context,
+                          private_subnet['id'],
+                          router['id'])