Manta Bommies lies on the outer reef off Lady Musgrave Island, in the Bunker Group at the southern end of the Great Barrier Reef. It is made up of isolated and scattered bommies rising from a sloping sandy bottom, and these coral heads act as cleaning stations for manta rays, which is how the site earned its name. Depths range from about 16 to 23 m, with shallower coral gardens near the reef, and visibility is typically 15-35 m.

The site is run as a drift dive and works on both the flood and ebb tides, with the current carrying divers across a large area of reef. That means more chance of encounters: as well as mantas, the operator lists turtles, eagle, bull and stingrays, and blacktip, whitetip, leopard, tawny nurse and even hammerhead sharks, plus lionfish, anemones with clownfish and pelagic fish. Dolphins are sometimes seen, and humpback whales pass between July and October.

The shallow coral gardens are colourful and good for photography, while the bommies are the place to pause and watch for mantas at the cleaning stations. The dive is guided by a divemaster with a free descent and free ascent, and the tender follows the group. Marine life writers describe the western-side Manta Ray Bommie as a collection of large coral-covered bommies with cleaner wrasse, batfish, reef sharks, coral trout, red emperor, snapper, barracuda, Maori wrasse, sweetlips, groper, cardinalfish, soft corals and gorgonians.

Manta Bommies suits Open Water divers with recent experience who are comfortable with a drift; operators require certification at booking. It is the headline dive of a Lady Musgrave day trip and, with the lagoon, the reason many divers make the long crossing.

Lady Musgrave Island is about 96 km north-east of Bundaberg and 59 km east of the Town of 1770. Lady Musgrave Experience departs 15-17 Marina Drive, Burnett Heads (15 minutes' drive from Bundaberg; parking at the marina) at about 7:30 am for a roughly 2-hour crossing to its pontoon in the lagoon; 1770 Reef Eco Tours leaves the 1770 Marina (free parking beside the marina cafe) for a roughly 90-minute run. Private vessels anchor inside the lagoon via the marked entrance channel through the reef.

Certified divers transfer from the pontoon to the custom dive tender Underworld for the short run (5-10 minutes) outside the lagoon to the outer-reef drift sites.

The lagoon itself is diveable in almost any weather, but the crossing is open ocean and tours are cancelled when south-easterly trade winds exceed about 25 knots or the swell is over 2.5 m. Outer-reef drift sites are chosen by wind and tide: the northern and western edges shelter from south-easterlies, the southern ledges need light winds or northerlies. Currents strengthen on spring tides and the outer sites are run as drifts on either the flood or ebb.

Cyclone season is November-April; summer storms and plankton reduce visibility. Calmest seas are often September-November and March-April. Manta Bommies is dived as a drift on either the flood or the ebb; stronger spring-tide currents carry divers further along the site.

Giant-stride from the tender Underworld at the up-current end, make a free descent with the divemaster to the reef edge and drift with the current along the wall or bommie line at the depth set in the briefing. Stay together behind the guide, check under overhangs and in the blue as you go, and ascend with the group for a free-ascent safety stop under the guide's SMB; the tender follows and collects the group.

Lady Musgrave Experience runs daily tours from Burnett Heads (Bundaberg) aboard Reef Empress to its Lady Musgrave HQ pontoon, with certified divers transferring to the dive tender Underworld for the 'Adventure Outer Reef Double Dive'; overnight stays on the pontoon allow extra and night dives. 1770 Reef Eco Tours also dives Lady Musgrave from the Town of 1770. Manta Bommies is the flagship outer-reef drift.