One of the things you do here is go for a ride on a big catamaran that leaves Tamarindo in early afternoon. The ship rounds a rocky point and anchors in a small cove where you can swim or snorkel. (Not us - it's the ocean for heaven's sake!). The crew serves a simple but very tasty buffet lunch (the gallo pinto was a wow), after which the boat returns to town at sunset.
It's always fun, even for me with paper white skin and bad balance when the waves roll. There are several of these tours. We took Marlin del Rey, and we can't say enough about the quality of the crew and food, and the great lengths taken to maintain a clean ship.