Any boat to anchor or stay someplace on mooring needs a ticket for NP Kornati. Tickets can be purchased for 1, 3, and 5 days. The 2023 price list can be viewed here.
You do not need the ticket only if you are staying at the "Marina Piškera" in Kornati because the access is included in the price of the marina. You can buy an entrance ticket on the spot, in Kornati, or at the Euronautic office.