Location: Southern side of the Osa Peninsula
The park protects major habitats including a montane forest, which covers more than half the park; a cloud forest, located in the highest region, richly populated by oaks and tree ferns; swamp forests, flooded practically all year-round; a holillo forest, predominated by palms; a mangrove swamp located on the estuaries of the Llorona, Corcovado and Sirena rivers; and a freshwater herbaceous swamp.
The park is home to some 500 species of trees, equivalent to a quarter of all the tree species in Costa Rica. Some of the larger trees include the Purple Heart, poponjoche, nargusta, banak, cow tree, espave and crabwood.
It protects several endangered species including cats and large reptiles. Moreover, it is home to several species of birds, which are either endemic or whose distribution is very restricted.
There are 140 species of mammals, 367 birds, 117 amphibians and reptiles, 40 types of freshwater fish, and there is an estimated of about 6,000 types of insects.
It is common to see large herds of white-lipped peccary, as well as troops of howler and spider monkeys. The park is a sanctuary to the largest population of scarlet macaws in the country.
Other species of birds found here are the king vulture, white hawk, short-billed pigeon, tovi parakeet and bronze-tailed sicklebill.