diff --git a/builtin/providers/aws/resource_aws_subnet.go b/builtin/providers/aws/resource_aws_subnet.go
index 2b1a0d063..a466c2ae9 100644
--- a/builtin/providers/aws/resource_aws_subnet.go
+++ b/builtin/providers/aws/resource_aws_subnet.go
@@ -41,6 +41,7 @@ func resourceAwsSubnet() *schema.Resource {
 			"ipv6_cidr_block": {
 				Type:     schema.TypeString,
 				Optional: true,
+				Computed: true,
 			},
 
 			"availability_zone": {