The Pacific south of Costa Rica, most especially the Osa Peninsula, Isla del Caño and surrounding area, is one of the world’s unique places distinguished by the fact that two distinct populations of humpback whales, come here to reproduce: those from the northern hemisphere (December-April) and those from the south (July-November),which makes sightings possible practically year-round. The best time is from July to November because the southern population is much more numerous and behaves more sociably, making the possibilities of sightings very high during this time.

In addition, the richly nutritious waters of the area attract the attention of various groups of the commonly seen resident spotted dolphins but also of bottle-nosed dolphins, rough-toothed dolphins and even huge groups of spinner dolphins in offshore waters.