Nope — adding multiple discounts or promo codes to your order is not possible. So if you have more than one code, use the one with the highest discount available to you. 

It is however possible to use Gift Card codes and volume discounts in combination with a discount code.   

Good to know, if you get a yearly Polarsteps Plus subscription, you'll get a 20% discount for all your Travel Book orders! For more information, please check out polarsteps.com/plus.