Astrochelys radiata is an endemic species and lives exclusively in the southwest of Madagascar. It is found in an area of about 21000 km2 between the rivers Onilahy and Mandrare. Today it still occurs naturally in a narrow belt of land extending from the coast to about 50 km inland. The main distribution area is on the Mahafaly and Karimbola plateaus. However, fossil evidence indicates that the species formerly occurred naturally in a much larger range.
Kept by locals as pets and living meat reserves, ray turtles are also found scattered in other regions of Madagascar. They are often kept with chickens and ducks by locals out of superstition, as they are believed to offer them protection from disease. Escaped animals may occur, but established populations outside the original range are considered unlikely. On the neighboring islands of Mauritius and La Réunion, Astrochelys radiata was introduced for food during the time of the seafarers. Today it is also bred there in large numbers in human care and under almost natural conditions.