The only microchiropteran endemic to the granitic Seychelles, the sheath-tailed bat Coleura seychellensis, is categorized as Critically Endangered on the IUCN Red List. Using bat detectors, the islands of Mahé, Praslin and La Digue were surveyed to establish the current distribution of this species. Although two new roosts were discovered on Mahé, no bats were observed on Praslin and La Digue, and the range of C. seychellensis appears to have further contracted in the last 2 decades. A total of 19 C. seychellensis were counted emerging from or entering three roosts in boulder caves on Mahé during 18 evenings of observations. The bats foraged in open coastal habitat, some of it anthropogenic, and their echolocation calls were also characteristic of bats feeding in open habitat. This study provides no evidence that C. seychellensis is dependent on forest or wetland for foraging. Dietary analysis indicated that C. seychellensis feeds on Coleoptera, Lepidoptera and Diptera. A public education programme to highlight the conservation status of the bat and the consequences of roost disturbance is recommended, together with the urgent need for legal protection of the bats and their roosts.