It is sometimes possible to combine the shipment of multiple lots from the same seller if the seller resides in the same country as you and the lots have been bought from the same auction on the same day.
In this case, you will only have to pay the highest shipping costs; this reduction will happen automatically. Please note that shipping costs can vary if you reside outside of the EU or in a country with special shipping regulations.
Some sellers may also offer to combine shipment for buyers not residing in the same country. To verify if this is possible for a particular lot, you can check the shipping tab on the lot page.
In case there is not this option, please contact the seller for more clarification. Catawiki has no influence in this matter. It needs to be agreed on by the buyer and seller directly.