The Southern Dropoff is the deepest and most exposed of the Breaksea Island sites, a wall on the ocean face of the island that drops to around 40 m. Marine Life Network rates it for experienced divers only and describes caves, sponge gardens and black coral trees, with abundant reef fish and invertebrates and schools of pelagic yellowtail kingfish, samson fish and silver trevally.

The site is shaped by the Southern Ocean: the granite is carved into overhangs and caves by swell, and the constant water movement feeds dense filter-feeder growth – sponges in every colour, gorgonians, and bushes of black coral at depth that are rarely seen on the sheltered sound sites. Blue groper, queen snapper and harlequin fish are common on the wall, and the pelagic schools that hang off the face on a good day are a highlight.

This is a dive for competent, deep-experienced divers who are comfortable with live-boat pickups, possible current and cold water. It is dived far less often than the island's northern sites because the weather window is so narrow, and when it is calm enough the dive shop may prefer the similarly exposed but shallower Blue's Canyon. Divers who get the chance, though, see Albany's temperate reef at its most pristine, with visibility that can exceed 25 m.

The site is a long way from recompression (Perth is 420 km away) and from shelter, so conservative profiles and nitrox with air tables are sensible, and the boat crew should carry oxygen and a clear evacuation plan.

Albany is 418 km (about 4.5 hours) south-east of Perth via Albany Highway. Charter boats and private boats launch either from the Emu Point boat ramp (Emu Point Drive, 7 km north-east of the CBD, with a large trailer car park, toilets and a fish-cleaning station) or from the town ramp beside the Albany Waterfront marina in Princess Royal Harbour, which exits into King George Sound through the harbour entrance past Possession Point. Breaksea Island lies across the entrance of King George Sound, about 9-10 km south-east of Emu Point (20-25 minutes by boat in good conditions, longer from the town ramp).

The Southern Dropoff is on the ocean side of the island, which requires rounding the island's western or eastern end; it is a live-boat drop in open water, only attempted in near-flat conditions.

Fully exposed to the Southern Ocean: diveable only when swell is under about 1 m and winds are light, which in Albany mostly means late summer and autumn highs, or a rare calm winter day with a northerly. Any southerly swell makes the entry and the surge at the base of the cliffs dangerous. Local operators decide on the day.

Drop onto the upper wall at 10-15 m, descend to a planned maximum (30 m recreational), and drift along the face with the wall on one shoulder, looking into caves and black coral trees. Ascend along the wall and deploy a DSMB for the safety stop so the live boat can pick you up.

Plan conservative no-decompression dives; nitrox recommended. Deeper profiles need deep/technical training and a DSMB for drifting deco.

Occasional trips by South Coast Diving Supplies for experienced divers in flat conditions; otherwise local club and private boats.