Gorgonia Hole is a shallow, relaxed dive on the northern side of Heron Reef and a favourite afternoon site. Its structure is a maze of cracks, crevices, small caves and short walls, many of them draped with gorgonian fans, which is where the site gets its name. Depths are mostly 7-16 m and the site is best dived at high water.

The holes and crevices are the point of the dive, as they hide a remarkable variety of creatures. Painted crayfish are common, lionfish hover in the overhangs, moray eels and angelfish patrol the walls, and nudibranchs graze the sponges. Green and loggerhead turtles, and occasionally hawksbills, use the site heavily; at low tide it is common to find turtles wedged into the cracks resting.

Because it is shallow and sheltered, divers can take their time and look closely, and a torch is useful for peering into the holes and bringing out the colours of the fans and sponges. It is an easy dive to navigate if you stay with the guide and follow the line of the reef. Gorgonia Hole suits all levels, including new divers and those doing training dives, and it is especially rewarding for macro photographers and turtle enthusiasts.

It features in the resort's top ten sites and is a good choice when the tide is high in the afternoon. It contrasts nicely with the bigger-animal cleaning station dives such as Heron Bommie and North Bommie, and gives a good sense of how much life hides in a Heron Reef crevice.

Heron Island is 72 km north-east of Gladstone. Fly or drive to Gladstone, then take the Heron Islander ferry from the Gladstone Marina terminal (72 Bryan Jordan Drive; check-in from 7:45 am, departs 9:30 am on scheduled days, about 2 hours), or transfer by seaplane or helicopter. Dive gear is carried on the ferry in addition to baggage.

On the island, the dive centre sits beside the harbour; boats leave the jetty for three dives daily and most Heron Reef sites are 5-15 minutes away. Gorgonia Hole is on the northern side of Heron Reef, about 5-10 minutes from the jetty, dived from a mooring.

Heron Reef sites are chosen on the day by wind and tide. The prevailing south-east trade winds (strongest April-September, often 15-25 knots) make the southern and south-eastern reef edge rough, so the sheltered northern and western sites are dived most. Northerly winds in spring and summer reverse this.

The tidal range is up to 3-4 m and currents run strongly around the reef edge and through Wistari Channel on springs; visibility is usually best on the incoming tide. Cyclone season is November-April; summer storms and plankton blooms can drop visibility to 10 m. Stingers are uncommon this far south but present in summer.

Gorgonia Hole is sheltered in south-easterlies and is best at high water; at low tide turtles often shelter in the cracks.

Descend to the reef at 10-12 m and slowly work along the walls and crevices with a torch, looking into each hole for crays, morays and resting turtles. Turn at half air and return a little shallower along the reef to the mooring.

Heron Island Resort Dive Centre is the only operator: three guided boat dives a day (about 9 am, 11 am and 3 pm) plus scheduled night dives, from the resort jetty; sites are rotated by tide and wind. Access requires a stay at Heron Island Resort (or the University of Queensland research station). Commonly scheduled as the afternoon dive.