Isolation has contributed over time to the development of humans culturally and biologically. The concept of isolation was popular in earlier anthropological and archaeological discussions of island settlement, but it has waned in favor of models emphasizing interaction. Although many islanders around the world developed sophisticated techniques for seafaring, these did not assure them of constant access to other peoples or places. Using case studies from the Pacific, we stress the importance that isolation played in island societies; the sea may have been a highway to some but for others it remained a difficulty to overcome. While we emphasize here the need to consider isolation factors in the archaeological study of islands, it is clear that we should move beyond the isolation versus interaction debate and recognize that, for varying environmental and sociocultural reasons, different levels of connections and separation existed between island peoples.