In 1642 Abel Janszoon Tasman, exploring for the Dutch East India Company, sighted the South Island. The Dutch named the new land for the province of Zeeland in the Netherlands. In 1769–70, the English explorer James Cook sailed around the two islands and revisited them for further mapping and exploration in 1773, 1774, and 1777. He claimed New Zealand for Great Britain, but the British government refused to establish jurisdiction over it.

Meantime a French expedition under Jean F. M. de Surville had stopped at New Zealand in 1770. In 1772 another party (whose leader, Marion du Fresne, was killed by the Maoris) claimed the country for France. With the founding of the Botany Bay colony in New South Wales (as Australia was then called) by Great Britain in 1788, New Zealand came into the British colonial sphere. Seal hunting at the southern end of the South Island began in 1792.

By the late 1790's United States whalers were working the waters off the North Island. The first settlement, of mixed nationality, grew up on the Bay of Islands. It was a lawless community of whalers, traders, seamen who had jumped ship, and runaway convicts from the Botany Bay colony.