This is the swimming hole (billabong) at Figtree Rapids. I know it doesn't look like rapids in this image, but that is because this shot is downstream from the rapids. This is about an hour hike up a pretty decent trail - be sure to put on your mosquito repellant - but well worth it. The swimming is great.
We didn't do it, but heard from the staff afterwards, you can hike further up the river (the Mossman), but it is not as good of a trail and requires crossing the river. Would like to do next time, but definitely suggest the shorter hike as well.