Three Sisters are a series of three large bommies lined up at the back of MillnReef. The deepest rises about 33m off the sand and within a metre of the surface. If there's a current start your first dive on the deepest bommie, see a giant school of fusiliers, various snapper and chub. As you go down the bommie walls you'll see barracuda. At the bottom see coral trout and cod move in and out of the overhangs andcrevices. There is black coral on the deepest side of the bommie.