Acoustic sampling for occurrence of the endangered Hawaiian hoary bat (Lasiurus cinereus semotus) was conducted at 18 “long-term” acoustic monitoring stations on 12 Hawaii Army National Guard (HIARNG) installations across the islands of Hawaii, Maui, Molokai, Oahu, and Kauai between 2012 and 2018. Bats were confirmed as present at 10 of these installations: Kealakekua Armory, Keaukaha Military Reservation (KMR), Hanapepe Armory, Kekaha Firing Range (KFR), Puunene Training Facility, Ukumehame Firing Range (UFR), Kaunakakai Armory, Bellows Regional Training Institute, Kalaeloa, Barber’s Point, and the 487th Military Parking Facility, Wahiawā. Our acoustic sampling did not record bat vocalizations at Fort Ruger and Waiawa Armory. Foraging activity was observed at nine acoustic monitoring stations on the islands of Hawaii, Kauai, Oahu, and Maui. No foraging activity was observed on Molokai and a single station on Oahu recorded one feeding buzz in September, 2017 at Kalaeloa, Barber’s Point.