What strait separates the two main islands of New Zealand?

The strait separating New Zealand’s two main islands is Cook Strait.

It lies between New Zealand’s North Island and South Island, connecting the Tasman Sea to the northwest with the South Pacific Ocean to the southeast. At its narrowest point, the islands are about 22 kilometres apart, although the full ferry route between Wellington and Picton is much longer.

The strait is named after British explorer James Cook, who established that the waterway separated the islands during his 1769–1770 voyage. Dutch explorer Abel Tasman had seen the area in 1642 but mistakenly believed it was a bay closed to the east. Māori tradition attributes earlier discovery to the navigator Kupe.

Cook Strait is famous for strong winds, heavy swells, and complex tidal flows. High water on one side can coincide with low water on the other, producing currents that may reach about five knots. A common mix-up is Foveaux Strait, which separates New Zealand’s South Island from Stewart Island, not the two main islands.