The Island measures 19.3 kilometres lengthwise from east to west and in width varies from 0.64 kilometres to 9.65 kilometres with an area of 92 square kilometres. The coastline is 133.5 kilometres including 40 km of beaches, it is the second largest of the Hauraki Gulf islands, the most populated and most accessible with regular ferry and air services. The port of Matiatia at the western end of the island is 17.7 km from Auckland and the eastern end is 21.4 km from Coromandel.

Waiheke Island is very hilly with few flat areas. The highest point is Maunganui at 231 metres. The climate is generally warmer than Auckland with less humidity and rain and more sunshine hours. There is a permanent population of around 7,000 residents.