Tasman Sea, arm of the S Pacific Ocean between Australia and New Zealand; named for Dutch explorer Abel Tasman. Sydney, Australia, is the largest city on the sea.

Part of the South Pacific Ocean, between southeastern Australia and western New Zealand. About 1,400 mi (2,250 km) wide, it has maximum depths exceeding 17,000 ft (5,200 m) in the Tasman Basin. Explored by Abel Janszoon Tasman in 1642 and by Capt. James Cook in the 1770s, it is notoriously stormy. Economic resources include fisheries and petroleum deposits.

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