After a drive through the rainforest to Golfito, you board a motorboat for a scenic 3-hour trip around Golfo Dulce, a fjord which separates Piedras Blancas National Park and the Osa peninsula. Due to the many rivers that flow into the gulf from the surrounding rainforest, the ocean is rich with minerals and provides a healthy food source for many marine animals and mammals. Three species of porpoise live and breed year-round in the gulf, and humpback whales can be seen at times. There is a 90% chance of observing bottlenose dolphins playing and swimming by the boat. It is not permitted to swim with the dolphins; you must remain in the boat.