Cayo Santa Maria is located in the Atlantic Ocean near the islands of Cayo Coco and Cayo Guillermo, on the north coast of the province of Villa Clara. It is connected to the mainland by a 48.6 km long Pedraplen dam. Nearby are the small islands of Las Brujas and Ensenchos.
Cayo Santa Maria itself is a miniature island only 13 km long and no more than 2 km wide, which belongs to the archipelago with the romantic name "Royal Gardens" (Jardines del Rey). The gardens, in turn, are under the care of UNESCO as an important biosphere reserve.