I would try a tour of the Tortuguero Canals. (everybody has you headed for water).
You are taken by bus to the canals. The bus tour itself is a nice informative tour. At the dock they have a local band playing and they serve pineapple , Bananas and other local fruit and cold drinks. You then get into covered /comfortable boats holding about 16 people with a driver and guide. Boat is powered by two large outboard engines. The canals are part natural and part manmade.
We saw dozens of water fowl and birds, monkeys, sloths , beautiful flora , crocadiles
and all kinds of beautiful stuff. They have clean bathroom facilities at the beginning and end of the trip. Even if it rains you are fine , boat is covered. Bus back to the ship.