diff --git a/variables.tf b/variables.tf
index f2f4669..56c5e38 100644
--- a/variables.tf
+++ b/variables.tf
@@ -16,6 +16,7 @@ variable "vpc_id" {
 variable "public_subnets" {
   type = list(string)
   description = "Public subnets (if set, private subnets are ignored)"
+  default = []
 }
 
 variable "private_subnets" {