Offshore from the family beach at Eagle Bay lies a very different dive. Marinelife.org.au describes 'coral bommies' - an offshore granite reef with pinnacles and ledges in 7-15 m - about 300-400 m from the beach, with diverse fish and pelagic species, reached by a 300-400 m swim, and notes that locals guard its location. It adds that other reefs 8-11 km offshore in 17-23 m require a larger boat.

The granite of the Cape Naturaliste peninsula forms rounded boulders and pinnacles quite unlike the limestone reefs further north, and in Geographe Bay's warm water these support corals, sponges and a good variety of fish. Western blue devils, wrasse, bullseyes and buffalo bream are likely around the ledges, with pelagic species such as trevally or samson fish passing.

The site suits fit shore divers comfortable with a long surface swim and navigation, or divers with a small boat. Because the position is not published, go with someone local or be prepared to search. A float and flag are essential on the swim, as boats run through this area to and from HMAS Swan and the Eagle Bay moorings.

Geographe Bay faces north, so Cape Naturaliste blocks most of the prevailing south-westerly swell and sea breeze that close the ocean coast; that shelter and the warm Leeuwin Current make the Dunsborough shoreline one of the most reliably diveable stretches of the South West, and winter north-westerly storms are the main thing that shuts it down.

From Dunsborough drive about 10 km to Eagle Bay and park on the foreshore. Strong swimmers can surface-swim 300-400 m offshore towing a float and flag; a small boat or kayak from Eagle Bay or the Dunsborough ramps is easier. Marinelife.org.au notes that locals guard the exact location, so local knowledge helps.

The nearest full-service dive shop for fills and hire is Swan Dive in Busselton; there is no dedicated dive shop in Margaret River or Augusta, so bring filled cylinders.

Sheltered from the south-west by Cape Naturaliste; best in calm conditions without northerly winds. The long surface swim is only sensible on flat mornings before the sea breeze; boat traffic heading to HMAS Swan passes nearby. General pattern in Geographe Bay: sheltered from south-westerly swell by Cape Naturaliste; summer mornings are calm before the afternoon sea breeze, while winter north-westerly fronts roll swell and chop into the bay and reduce visibility for several days.

Surface-swim or boat to the bommies, descend on the granite and circuit the pinnacles and ledges at 7-15 m, then return on a compass bearing to the beach. Agree a turn pressure before descending (half gas, or a third where current is likely), carry a DSMB, and make a 3-minute safety stop at 5 m.

No regular operator; local divers from shore or small boats. Nearest dive services: Swan Dive (Busselton/Port Geographe) for fills, hire, nitrox and charters; no dive shop in Margaret River or Augusta.