Arid environments are characterized by resource fluctuations that lead to spatial and temporal variability in species abundance, resulting in low species diversity. This study aimed to determine the activity patterns and habitat use by bats in an arid environment in western Algeria (Bechar region). In 2016, six sites were studied using acoustic bat detection. A total of 10 species were reported: Asellia tridens, Rhinopoma cystops, R. microphyllum, Tadarida teniotis, Miniopterus schreibersii, Eptesicus isabellinus, Hypsugo savii, Otonycteris hemprichii, Pipistrellus kuhlii (including P. kuhlii kuhlii and P. kuhlii deserti) and Vansonia rueppellii. Activity varied considerably from month to month and from site to site. Bats were particularly active in the spring and autumn. The first activity peak coincides with pregnancy (late April), followed by relatively low activity in August, probably due to summer torpor induced by high temperatures. The second peak in October coincides with mating and storage reserves before winter. Water bodies, oasis and urban lights concentrate bat activity. These results confirm the previously reported major role of water bodies in arid environments for bats. Further surveys should be carried out in the region and conservation measures should be taken to protect known roosts.