Isla del Coco is the summit of a seamount 500 km southwest of Costa Rica’s mainland. The island is surrounded by a platform about 18 km long that trends in a southwest-northeast direction with a break in slope at around 180 m deep. Since 2006 the DeepSee submarine, with a 450 m depth capability, has been exploring the deep-water environments of Isla del Coco. Videos have been taken and several preliminary conclusions reached about the deep-water fauna of the island. First, the fauna changes rapidly at about 50 m depth; second, the fauna is highly diverse, with many new species likely; third, even though the distance between the north and south sides of the island is less than 8 km, the faunas seem to be different, possibly due to the influence of differing deep-water currents on each side of the island; and fourth, groups of organisms that where thought to be absent in the eastern Pacific Ocean have now been photographed. DeepSee has opened a new window to a very little known world of Isla del Coco. More studies are necessary to understand the deep-water faunas, and their relation to shallow water organisms and environments. This information will be important for management and conservation of the marine biodiversity of Isla del Coco.