The strait separating Wellington’s North Island location from New Zealand’s South Island is Cook Strait.
Cook Strait connects the Tasman Sea on the northwest with the South Pacific Ocean on the southeast. Wellington lies on the North Island’s southwestern coast, while the South Island begins across the water. The strait’s narrowest point is about 22 kilometres wide, although the exact measurement depends on which headlands or islands are used as reference points.
The waterway is named after James Cook, who became the first European commander to sail through it in 1770. Māori knew the strait as Te Moana-o-Raukawa, and Māori communities crossed it long before European exploration. Today, regular passenger and freight ferries connect Wellington with Picton in the Marlborough Sounds.
The wrong options are other New Zealand or Australian waterways. Foveaux Strait separates New Zealand’s South Island from Stewart Island, while Bass Strait separates mainland Australia from Tasmania. Torres Strait lies between Australia and New Guinea, so none of those names fits Wellington’s setting.