The Costa Rican boarder at Los Chiles. The easiest and relaxed boarder crossing so far - Costa Rica to Nicaragua by boat up the Frio River. It was like a nature-tour. The boarder town San Carlos, Nicaragua. A really nice little town at the waterfront. San Carlos to Isla de Ometepe - seven hours by ferry. Lake Nicaragua San Carlos from the ferryLake Nicaragua, on the way from Isla de Ometepe to the mainland.