chunder down under

There are quite a few good swimming holes in the area around Cairns, although you will need a car to get to them. Stony Creek is one, Crystal Cascades is probably more popular. It's a series of pools connected by rapids (which you can body surf down in some places) and is ideal on a hot day as the water is, initially, VERY cold. However, once you're in it's ok and cools you down from the day's heat. No danger from crocs either!