Meet the site
The Aldinga Pinnacles are the gentler partner to the Drop-off, a cluster of about ten rock pinnacles closer inshore within the Aldinga Reef Sanctuary Zone. The Marine Life Network describes them rising from around 20 m to about 5 m, while the Federation and the Dive Shack give a typical depth of about 8 m on the reef around them. On clear days they can be seen from the surface. The pinnacles are sculpted limestone with swim-throughs, overhangs and ledges, and they are covered in weed growth on top and sponges, soft corals and ascidians on the shaded sides. The Marine Life Network describes a staggering amount of fish – blue devils, bullseyes, boarfish and old wives – and plenty of nudibranchs for macro photographers, calling the site a photographer's paradise. Because the reef is unfished, the fish are relaxed around divers. The area is also considered a snapper breeding ground. The Dive Shack recommends around 60 minutes of bottom time and notes that visibility is generally very good. With the tops in 5-8 m and the most interesting structure in 8-12 m, the Pinnacles make a long, relaxed dive, ideal as the second dive after the Drop-off or as a first Aldinga dive for Open Water divers. The same caution applies as at the Drop-off: local sources advise against diving the offshore reef when snapper are running because white sharks sometimes follow them. Outside those periods, the Pinnacles are one of the most rewarding reef dives in the Adelaide region.
What you might see
Blue devilfish, bullseyes, boarfish, old wives, snapper (breeding area), morwong, wrasse, nudibranchs, soft corals, sponges, ascidians
Location
Group of about ten limestone pinnacles rising from the seabed to within about 5 m of the surface, inshore of the Aldinga Drop-off within the sanctuary zone.
Facilities nearby
O'Sullivan Beach boat ramp.
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
marinelife.org.ausdfsa.netthediveshack.com.audivedb.netRecord updated 26 Sept 2026. Source claims are being reviewed.