The American sweet potato (Ipomoea batatas) is a globally important comestible crop that features prominently in Polynesian lore; however, the timing and mode of its Oceanic transplantation remain obscure. New research from the Māori cultivation site M24/11 in Aotearoa/New Zealand, presented here, offers a re-evaluation of evidence for the early use and distribution of the sweet potato in southern Polynesia. Consideration of plant microparticles from fourteenth-century archaeological contexts at the site indicates local cultivation of sweet potato, taro and yam. Of these, only sweet potato persisted through a post-1650 climatic downturn it seems, underscoring the enduring southern-Polynesian appeal of this hardy crop.