Choose from 38 Sierra Designs coupons that include promo codes and free shipping deals for May 2017. Our top coupon is a 20% Off coupon code. Use a promo code to save on outdoor gear and apparel at Sierra Designs. Built in the Rockies for the great outdoors, you'll find everything from tents to sleeping bags from Sierra Designs. Ensure you're next outdoor adventure is well-provisioned with all the gear you need.