Covering 140 square kilometers, this is the largest of all the national parks and includes the islands of Beata and Alto Velo. Receiving an annual average rainfall of only 10 to 28 inches, the vegetation is mostly subtropical dry forest and thorn forest, cacti being the most predominant.

Approximately sixty percent of the country’s species of birds inhabit the region, among them the nation’s largest population of flamingos, as well as American frigate birds, roseate spoonbills, black-crowned tanagers, great egrets, herons, terns, and spoonbills. In 2001 scientists identified the world’s smallest gecko on Alto Velo - the Dwarf Gecko (Sphaerodactylus cochranae) measures 1.6 centimeters across.

The Ricord iguana (Cyclura ricordii) and the rhinoceros iguana (Cyclura cornuta) also inhabit the region, both of which are endemic to the Dominican Republic. On the southern coast of Isla Beata there are caves with Taino pictographs and petrographs.