Many people use San Carlos as a passageway to Los Chiles, Costa Rica. Every day from Monday to Saturday two boats leave the harbor at 10:00 a.m. and 4:00 p.m. On Sunday there is one boat that leaves at 2:30 p.m. You should try to get to the dock half an hour early in order to secure a place on the boat. The ride takes about an hour and costs $10.00. The crossing takes you directly to Costa Rican customs, where there is an occasional wait and a border-crossing fee of $7.00. There is also the option to buy private trips to Costa Rica for $70.00 with local transportation companies that will get you through the border quickly and seamlessly. Ask about this option at the harbor.