Harry's Bommie is a Heron Reef site that begins at one large bommie, which marks the start of the dive, and then leads divers along a line of further bommies set among forests of hard coral. The dive's appeal is its unpredictability: each bommie has its own residents, and the guides like to say that you never know what will appear around the next one. The hard coral forests between the bommies are thick with damselfish and fusiliers, and the bommies themselves shelter a range of reef fish, crustaceans and invertebrates.

Encounters listed by the dive team include a giant starry puffer, tawny nurse sharks resting on the sand, and brightly coloured nudibranchs on the coral heads. Turtles and reef sharks can turn up here as at any Heron site. The layout is easy to follow: a string of coral heads at moderate depth, so divers can choose how deep to go and how long to spend at each.

That makes it a good site for mixed groups and for divers on their first few dives at Heron who want variety without complexity. Photographers will find plenty of subjects for both wide-angle images of the coral forests and macro shots on the bommies. Because the dive covers a fair distance, it is often done with a slight current, and the boat can collect divers at the far end if needed.

The name should not be confused with 'Harry's House', a nickname for Turtle Gully linked to a great hammerhead seen there. Harry's Bommie was grouped with several other sites in the earlier database pass and is now listed on its own.

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. Harry's Bommie is a short boat ride (5-10 minutes) from the jetty, dived from a mooring near the marker bommie.

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 large marker bommie, circle it, then move from bommie to bommie along the reef slope at 10-15 m with the current if any. Turn at half air and return a little shallower through the hard coral forest to the start bommie for the safety stop.

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).