The Polmaise Bommies lie on Polmaise Reef, just south-west of Masthead Island in the Capricorn Group. They are one of the few Capricorn sites outside Heron and Lady Musgrave with a published position and description, listed by the Marine Life Network with depths of 16-20 m and visibility of about 20 m. The bommies feature overhangs and swim-throughs that make for an interesting, structured dive, and they shelter a good mix of fish.

Lionfish hover under the overhangs, crayfish hide in the cracks, and coral trout and barramundi cod patrol the bommies. As with most Capricorn reefs, turtles and reef sharks are likely visitors. Because there is no operator, the site is visited only by private boats, camping groups at Masthead and the occasional liveaboard.

Divers should plan to be self-sufficient and approach the swim-throughs cautiously, checking that each is open and wide before entering. The Polmaise Bommies are a natural pairing with the Tambaroora wreck, which lies in only 8 m on the same reef and makes a good shallow second dive. Together they make Polmaise Reef one of the more interesting destinations for private boats in the Capricorn Group.

The site suits divers with Advanced certification or equivalent experience, given its depth, remote setting and the likelihood of current. With few divers ever visiting, the bommies retain large, undisturbed fish, and a slow approach usually lets divers get close to the cod and trout sheltering in the overhangs. Bring a torch to light the recesses of the swim-throughs.

The Capricorn Group lies 60-100 km north-east of Gladstone. Private boats launch from Gladstone Marina (Bryan Jordan Drive; ramps, fuel and trailer parking) and cross the shipping approaches and open water, typically 2-4 hours depending on vessel and destination; the Capricorn Bunker liveaboards that occasionally visit depart Gladstone or Yeppoon (Rosslyn Bay) and anchor overnight in the lee of the cays. Camping on the national park cays requires a QPWS permit and a camper transfer or private vessel.

Polmaise Reef lies just south-west of Masthead Island, roughly 2-3 hours by private boat from Gladstone; the published position is 23°34.401'S 151°41.974'E. Anchor on sand nearby, clear of the coral.

The Capricorn cays are exposed to the south-east trades (often 15-25 knots April-September), which make the Gladstone crossing rough and restrict diving to the lee (north-western) sides. The calmest windows are typically September-December and March-April. Northerlies in spring and summer reverse the sheltered sides.

Tidal currents run strongly around reef edges and channels on springs. Cyclone season November-April. Polmaise Reef is open to the trade winds; dive in calm spells or on the lee side.

Current is strongest on spring tides.

Descend to the base of the bommies at 18-20 m, explore the overhangs and swim-throughs (all short and open), then work around the bommies at a shallower level before returning to the anchor for the safety stop.

No daily operator. Occasional liveaboard itineraries (for example the 8-diver MV Adori run by Professional Dive Services, 4 days/3 nights from Yeppoon) and fishing/snorkel charters such as Eastern Voyager visit the Capricorn cays; otherwise private boats and camping groups only.