The drivers and motivations that lie behind the expansion of Lower Pleistocene hominin populations into Eurasia and the Far East are still being debated. One key factor is thought to have been the expansion of grassland and open woodland habitats beyond Africa. Early hominins—scavengers or hunters, with or without habitual use of fire—evolved and were adapted to survival in this biome. Where we find comparable settings outside Africa we consider these more likely to have sustained a tropical savannah primate. The late survival of archaic hominin forms in Southeast Asia has recently been linked to the persistence of the open and arid landscape during the Pleistocene to the extent that the area may even have constituted a refugium. While there is compelling evidence for longer term trends of increasing aridity and habitat fragmentation from the late Pliocene onwards, recent paleontological, and paleoenvironmental studies in Asia as well as in Africa indicate that Pleistocene landscapes were more heterogeneous than previously thought. The encounters, constraints, and opportunities this presented hominin populations meant that selection pressures shaped diverging morphological and behavioral trajectories between dispersal lines across the Western and Eastern provinces of the Old World. This brief thematic overview of the early history of hominin occupation in East and Southeast Asia explores the effects of that divergence.