The lakes are formed in three different ways, window lakes, perched lakes and barrage lakes. Window lakes such as Yankee Jack and Ocean Lake are formed when the ground drops below the natural water table.

Perched lakes such as Lake Bowarrady which is 120 meters above sea level are formed by rainwater being caught in saucer-shaped depressions with a hard impervious base of organic matter. Lake Boomanjin at approximately 190 hectares in total area and is the Australia’s largest perched lake. Other perched lakes on the island include Lake Birrabeen and the very popular Lake McKenzie.

Lake Wabby is especially unique as it is formed by the damming effect of a sand blow blocking the waters of a natural spring. Wabby is close to the eastern beach side of the island and unlike the other lakes it supports several species of fish.