Between May 2014 and May 2015 the evening emergence of the great leaf-nosed bat Hipposideros armiger was studied at a lowland roost in Hong Kong, PRC. Average emergence of H. armiger was 14.6 ± 6.1 min after sunset. There is a strong correlation between first emergence and civil twilight (r = 0.968, P < 0.0001) and also a strong correlation between last emergence and civil twilight (r = 0.977, P< 0.0001). No bat emergence was noted during December and January, the colder months of the year. The species is widely distributed in Asia though little had been published on its basic ecology when compared to bat species in temperate regions. It is hoped that understanding of the seasonal emergence of Hipposideros armiger will help in further investigations of ecology and conservation of this bat species.