Plate Ledge is a large dive site on Heron Reef with a gradual slope reaching a maximum of about 16 m. It is characterised by many gutters and channels to explore, with scattered coral formations on terrain that is predominantly rocky, giving it a different look from the densely coral-covered sites nearby. The standout feature is the gorgonian fans, which grow to an impressive size on the slope and channel sides.

Various species of sharks and manta rays frequent the area, and closer to the bottom divers may find octopus and stonefish hiding among the rocks. The gutters and channels allow a meandering, exploratory dive with plenty of variation, and because the site is large, guides can vary the route from one visit to the next. The rocky bottom means careful buoyancy is important, both to protect the fans and to avoid unintentionally touching a camouflaged stonefish.

Plate Ledge suits Open Water divers with reasonable buoyancy control, and it offers photographers wide-angle possibilities with the big fans as well as macro opportunities in the crevices. It is less often mentioned than the top-ten sites but provides good variety for divers staying on the island for a week. Plate Ledge was grouped with several other Heron sites in the earlier database pass and is now listed separately because it has its own published description.

Octopus are often found in the rocky crevices, especially later in the day, and the channels provide shelter for resting reef sharks. The site's size means that two dives here can feel quite different.

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. Plate Ledge is a short boat ride from the jetty.

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.

Descend to the slope and explore the gutters and channels in a loop, reaching the deepest point of around 16 m early and working shallower. Check the gorgonian fans for small life and watch the rocky patches for stonefish before touching down anywhere.

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).