Southpark marks the southernmost point of Heron Reef. There is no mooring, so the dive begins with a free descent to about 10-12 m, after which divers can follow the reef down to around 20 m. Because it sits on the exposed southern edge, it is dived less often than the northern sites, but it is known for the outstanding health and variety of its hard corals.

The dive team counts around 20 different kinds of hard coral growing on the site, along with all the fish that live among them. Scorpionfish lie camouflaged on the coral, mantis shrimp live in burrows and holes within the formations, and large tawny nurse sharks rest beneath the deeper bommies. The site suits divers with some experience of free descents and live-boat pick-ups, ideally Advanced certification.

Buoyancy control matters, both to protect the coral and to hold position when the current runs along the reef edge. For coral enthusiasts, Southpark is one of the best places on Heron Reef to see a wide range of hard coral growth forms in good condition in one dive. Photographers should bring a wide-angle lens for the reef-scapes and look for the mantis shrimp and scorpionfish for macro.

Because it depends on calm conditions on the south side, ask the dive team to let you know if a suitable weather window appears during your stay. The south side also tends to receive cleaner oceanic water than the channel sites, so on the right day visibility can be among the best on Heron Reef, and the coral colours show well in the clear water.

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. Southpark is at the southernmost point of Heron Reef, about 15-20 minutes by boat from the jetty; there is no mooring, so the boat drops divers for a free descent and collects them on SMBs.

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.

Southpark is on the southern edge of Heron Reef, directly exposed to the prevailing south-easterlies, so it is dived only in light winds or northerly conditions.

Free-descend to 10-12 m on the reef, then follow the slope down to the deeper bommies at 18-20 m, checking underneath for tawny nurse sharks. Work back up through the hard coral zone, surveying the variety of species, and deploy an SMB for the safety stop and live-boat pick-up.

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). Dived when the south side is calm.