The Tobago Cays are an archipelago comprising five small uninhabited islands - Petit Rameau, Petit Bateau, Baradol, Petit Tobac and Jamesby - located in the Southern Grenadines. The Tobago Cays are now the key element of the Tobago Cays Marine Park, a national park and wildlife preserve run by the St.Vincent and the Grenadines government. The Tobago Cays Marine Park consists of a 1,400-acre (5.7 km2) sand-bottom lagoon which encompasses four uninhabited cays and the 4 km Horseshoe Reef. While the cays are uninhabited, they are surrounded by the three larger inhabited islands of Union Island, Mayreau and Canouan.
The most extensive and well-developed coral reef complexes in St. Vincent & the Grenadines occur on shallow shelves around the windward sides of Mayreau and Union Islands and the Cays themselves. In addition, principal vegetation types include beach vegetation and dry forest. With the exception of a small mangrove in Petit Rameau and salt pond in Mayreau, there are no wetlands in the Cays.
Major users of the area include: cruise ships (an estimated 50,000 visitors each year of which 10,000 visit the Cays); yachts (an estimated 3,000 yachts anchor in the lagoon each year); day charters (from nearby hotels); sport divers and snorkelers; and fishing enthusiasts.