Estimating large carnivore population size and understanding how individuals share space is crucial for their conservation, even more so now they are increasingly restricted to small, fenced game reserves where active management is often required. Combining data from GPS collars and camera traps, we estimated population size for leopards (Panthera pardus) on Ongava Game Reserve, northern Namibia, and investigated their spatio-temporal use of waterholes. Over three years of camera trapping, we identified a total of 29 individuals (including 12 adult or sub-adult females and 15 adult or sub-adult males). Based on the time interval over which they were observed, we defined 10 of these individuals as resident (four adult or sub-adult males and six adult or sub-adult females). The remaining 19 individuals (66%) were classified as transient. During the same period, we deployed two GPS collars, one on a resident adult male, the other on a resident adult female. Home range sizes from GPS data were estimated at 193 km2 for the male and 122 km2 for the female. Based on home range overlap found in the literature, we estimated Ongava’s resident population to be composed of 2-4 males and 3-6 females. We found no evidence of exclusive use of waterholes by individuals, suggesting an absence of spatial avoidance. Our work highlights the importance of taking social status (resident vs transient) into account and of using multiple methods when estimating population size of leopards. Keywords: Panthera pardus, home range, camera trap, overlap, GPS collar, population size, leopard, Namibia, spatial ecology.