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.

Astrochelys radiata lives in areas with a pronounced dry season and vegetation dominated by thornbush savanna. The local habitat is mainly dominated by succulent and thorny plants, especially from the Didiereaceae and Euphorbiaceae families. The scrub vegetation is dominated by Diospyros sp. (Seddon et al. 2000). It likes to colonize areas with low and dense vegetation and those dominated by opuntia cacti after deforestation and overgrazing. In general, the habitats in which Astrochely radiata is found are classified under xerophytic forest and bush landscape summarized.

By grazing grasses and treading out small trails in the scrub, Radiated Tortoises make room for small-growing and water-storing succulents. By ingesting and excreting undigested seeds, Astrochelys radiata also ensures the spread of sometimes rare, endemic plant species in their habitat. Radiated tortoises thus prove to be gentle gardeners and architects of an extremely sensitive ecosystem.