Rio Claro is a pristine and wild river located around 1 hour South from Drake Bay. There is a trail along the coast, passing by several coves and hidden beaches and also rainforest with abundant wildlife that connects Drake Bay with Rio Claro. The hiking trail is public, and therefore can be a great thing to explore on a day at leisure. You might very well encounter white faced monkeys, toucans and mammals like the Coati Mundi and the Racoon.
Once at Rio Claro, there is a nice beach for swimming and bathing ( care should be taken as in all the beaches ). By the estuary, you can also rent canoes to explore the river inland, or pay for a boat keeper to transport you to the other side. On the other side, the trail continues to San Josecito beach, and beyond, San Pedrillo, the northernmost Corcovado National Park entrance.