Competition is a source of dispersal pressure in past and present species. Australasia provides an opportunity to assess the effects of competition on dietary and spatial niche partitioning behaviour in humans as they encountered both placental and marsupial carnivores during dispersal through Australasia (~80–50ka). Here, we investigate the relationship of early modern humans to mammalian carnivores to assess humans’ place within local carnivore guilds, both above and below the Wallace Line. We employ the competition index (CI), which assesses ratios of prey overlap based on body mass to estimate the potential for competition between two species on a scale of 0 (no prey overlap, no competition) to 1 (full prey overlap, maximum competition). We compare Late Pleistocene data from 5 sites in Laos and Vietnam to 4 Australian Kimberley sites. Results demonstrate that humans were likely subject to competitive pressure from concurrent mammalian carnivores in Southeast Asian landscapes due to extensive prey choice overlap, particularly with medium-sized prey specialists such as hyenas, dholes, and leopards (CI= 0.60, 0.50, and 0.66, respectively). However, the type of hunting method (solo ambush vs. group hunting) affected the degree of competition, with group hunting practices reducing likely competitive pressure for medium-size prey, particularly from leopards. Results indicate humans were unlikely to face competitive pressure from mammalian carnivores at the Australian sites (CI≤ 0.125), irrespective of hunting method. These data suggest that hunting behaviour may have been used as a strategy along with dietary and spatial partitioning to reduce competitive pressure during human dispersal through Southeast Asia. Humans did not experience similar competitive pressures in the Kimberley due to the comparative reduction of large mammalian carnivores across the Wallace Line. We suggest that biotic interactions should not be overlooked in studies of human dispersal behaviour.