The Tasman Sea (Maori: Te Tai-o-Rehua) is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer Abel Janszoon Tasman, who was the first recorded European to encounter New Zealand and Tasmania. The British explorer Captain James Cook later extensively navigated the Tasman Sea in the 1770s as part of his first voyage of exploration.

La mer de Tasman (parfois erronément appelée mer de Tasmanie), dans le Pacifique Sud, est située entre la Nouvelle-Zélande, l'Australie et la Tasmanie.