Endemic insular species are particularly vulnerable to anthropogenic threats. The fish-eating bat Myotis vivesi is restricted mainly to the islands of the Gulf of California in Mexico and although several aspects of its biology have been studied there are no recent accounts of its current distribution. We conducted several expeditions during 2001–2016 to verify the current geographical distribution of this bat, and to record the presence of introduced predators. We identified the localities in which maternity colonies occur, estimated the size of the bat population on Partida Norte Island in 2003, and monitored bat presence on this island during 2004–2016. We found fish-eating bats on 36 islands and maternity colonies on 19 islands. Introduced rats Rattus rattus or cats Felis catus were captured on seven islands where the bats were present, and on five islands where they were absent. We estimated a population of c. 30,000 fish-eating bats in May 2003 and we confirmed the species’ presence on Partida Norte Island during 2004–2016. Based on the information compiled from our surveys and previous studies, we discuss the adequacy of the species’ current categorization as Vulnerable on the IUCN Red List, and its conservation status conferred by Mexican conservation authorities.