Isla del Coco being the only portion to appear above sea level. It presents a rugged relief characterized by an irregular coastline with cliffs rising almost vertically from a narrow shore to heights of 200m. Inland, the terrain is mountainous with numerous rivers and streams, many of which plunge over the peripheral cliffs in spectacular waterfalls. The Genio and Pittier rivers are the largest watercourses, draining their waters from the mountains of the interior and flowing into Bah a Wafer. The Lievre Creek flows into Bah a Chatham.
Soils are very acidic entisols.
The underwater profile consists of stepwise shelves with almost no intertidal zone and a shallow submerged fringing reef, culminating in sand and Porites rubble at the edge of a several hundred metres deep trench. The most important reefs are located in Punta Mar a, Punta Presidio, Punta Pacheco and some areas of the Iglesias, Chatham and Wafer Bays. The climate is strongly influenced by the eastward-flowing Equatorial Counter Current. The vegetation is exuberant and owes its lushness to the heavy rainfalls and rugged relief, which favours condensation. Major vegetation type corresponds to Holdridge premontane rain forest life zone.