The bat fauna from the extreme north of Chile is poorly known, principally due to a lack of dedicated surveys. To better assess the diversity of bats there, we conducted acoustic surveys at Arica city and three coastal valleys (Azapa, Lluta and Camarones) in the Arica and Parinacota region, Chile. We obtained 82 acoustic records of the Peale's free-tailed bat (Nyctinomops aurispinosus) in nine sites within the region. This species had not been previously documented in Chile but was known from adjacent Tacna province, Peru. Echolocation calls of N. aurispinosus can be distinguished from other molossid bat species occurring in the area by its lower frequency range. Our data suggest a wide distribution of N. aurispinosus across the coastal valleys of the Arica and Parinacota region, where they were active in both natural and anthropized habitats. This southernmost record of N. aurispinosus for the Pacific coast, extends its known range ca. 150 km southward, and increases up to 15 the number of bat species in Chile.