Ponui Island, also known as Chamberlin's Island, is located in the Hauraki Gulf, to the east of the city of Auckland, New Zealand. It is located to the southeast of Waiheke Island, at the eastern end of the Tamaki Strait, which separates the island from the Hunua Ranges on the mainland to the south.
The island has an area of 18 km² and has been farmed by the Chamberlin family since 1853. The island now consists of three farms, two owned by the Chamberlin family and one by John Spencer. The only permanent inhabitants (nine in the 2001 census) are associated with the farms which are predominantly used for sheep.
The island is a popular site for youth camps for organisations such as Scouts. Crusader camps (now under the banner of Scripture Union) have been held on the island since 1932.
The island is the home of New Zealand's only feral donkey breed, the Ponui donkey and also New Zealand's national bird, the kiwi.
Coordinates: 36°52′S 175°11′E / 36.867°S 175.183°E