There are three coral cays in the group. The largest, North Cay, is usually submerged only being exposed at by the lowest tides.  The smallest, Mid Isle, is approximately 300m in diameter with an elevation of 6m.  The most southerly, officially named South Cay but known more commonly as Willis Island is usually 475m long, 166m wide, with an elevation of 9m. The north-east end of the island consists of loose course coral fragemnts and sand and in stormy weather it has been know for up to 30m of this to be washed away; only to be gradually restored by the prevailing SE Trade Winds. There is no real lagoon as such, but the sheltered side of the cay offers relatively shallow and safe diving with a lot of good undamaged features.  To the east of the island the mostly submerged cay extends in an arc approximately 2km south. It is shallow and often exposed at low tides, making for iinteresting walks. The eastern edge offers spectacular coral gowths which cling to what looks like an escarpment which falls away rapidly to the deep.. Ominious, but beautiful.

450km east of Townsville and Cairns.

Willis Islets is also known as Willis Group.