 They settled in what are now islands mostly through land migrations into the coastal lowland plains of Sundaland and Sahul, most of which are now underwater.Humans reached the islands in Wallacea as well as the Sahul landmass (Australia and New Guinea) by around 53,000 BP (some give even older dates up to 65,000 BP).By 45,400 years ago, humans had reached the Bismarck Archipelago in Near Oceania.