diff --git a/vpc-transit-gateway-association/data.transit-gateway.tf b/vpc-transit-gateway-association/data.transit-gateway.tf
index 1ecaf82..b32a619 100644
--- a/vpc-transit-gateway-association/data.transit-gateway.tf
+++ b/vpc-transit-gateway-association/data.transit-gateway.tf
@@ -35,7 +35,7 @@ data "aws_ec2_transit_gateway_route_table" "route_tables_self" {
 }
 
 locals {
-  transit_gateway_route_table_ids_self = { for k, v in data.aws_ec2_transit_gateway_route_table.route_tables_self : v.tags["boc:network_vrf"] => k }
+  transit_gateway_route_table_ids_self = { for k, v in data.aws_ec2_transit_gateway_route_table.route_tables_self : v.tags["boc:network_vrf"] => k if contains(keys(v.tags), "boc:network_vrf") }
 }
 
 #---
@@ -56,5 +56,5 @@ data "aws_ec2_transit_gateway_route_table" "route_tables_peer" {
 }
 
 locals {
-  transit_gateway_route_table_ids_peer = { for k, v in data.aws_ec2_transit_gateway_route_table.route_tables_peer : v.tags["boc:network_vrf"] => k }
+  transit_gateway_route_table_ids_peer = { for k, v in data.aws_ec2_transit_gateway_route_table.route_tables_peer : v.tags["boc:network_vrf"] => k if contains(keys(v.tags), "boc:network_vrf") }
 }