The Kōhaihai River (Māori: Kōwhaiwhai) is a river of the northwest of New Zealand's South Island.

Flowing southwest and then west from the Dommett Range, the river's entire length is within the Kahurangi National Park.

The river's mouth marks the south western end of the Heaphy Track and the northern terminus of the West Coast's road system.

"Place name detail: Kohaihai River".

This article about a river in the West Coast Region of New Zealand is a stub.