Platte Island or Île Platte is an island in the Southern Coral Group that is part of the Outer Islands of the Seychelles. The island is located south of the Seychelles Bank at 05°52′S 55°24′E. Coëtivy Island (also Southern Coral Group) lies 171 kilometres further southeast. Platte Island is located 130 kilometres south of Mahé, the main island of the Seychelles, and 140 kilometres from their capital Victoria.The island, a low and wooded sand cay, ranges about 1,300 metres from north to south, with a width from 250 metres in the south to 550 metres in the north and a land area of 0.578 square kilometres. Its height is 3 m above the sea level. Barrier reefs, over which the sea breaks heavily, extend 5 kilometres north, 0.8 kilometres east, and 2.4 kilometres south of the island, making it a pseudo-atoll. Within the barrier reefs, the lagoon is quite smooth, and landing is safe and easy. A submerged coral reef rim extends 12 kilometres west and 18 kilometres south of the island, obviously the remnants of a sunken atoll, creating a complex of almost 25 kilometres in length north—south and 14 kilometres in width east—west and covering an area of roughly 270 km2. There are two tricky passages through the reef on the northwest side, available only for small vessels with local knowledge only. La Perle Reef lies at the southwestern end of the reef rim, about 10 kilometres southwest of Platte Island. Depths of less than 4 metres can exist on this reef where breakers have been observed.