Sophora chathamica is one of 8 species of native sophora in New Zealand. It grows naturally in the north-west of the North Island in New Zealand, as far south as the Tongaporutu River in north Taranaki, and as far north as Te Paki. It can also be found growing near Wellington and the Chatham Islands, although these later plantings are thought to be a result of Maori plantings in the late 18th century and early 19th century. It is primarily a species of coastal forest, often on cliff faces or banks overlooking estuarine rivers or inlets.

Sophora chathamica can grow up to 20 metres tall but usually is much smaller. It generally flowers from August until November. The 3 cm long yellow flowers are on drooping bunches. There are >12 seeds in >180 mm long brown 4-winged pods during October-September. The leaves are >150mm long with leaflets 6-16mm long by 4-8mm wide. The oval leaflets are larger than other kowhai species (except S. tetraptera) and they overlap. They have a fine white tomentum on the underside. Unlike many kowhai species, coastal kowhai lacks the divaricating juvenile stage.