Austinmer is one of the prettiest beaches in the northern Illawarra, and the rock platform at its southern end, beyond the twin ocean pools, gives access to a shallow reef that local divers and snorkellers use on calm days. It is documented mainly through local knowledge and condition-report services rather than dive guides, so expect a relaxed exploratory dive rather than a marked route.

The reef starts under an Ecklonia kelp canopy close to the platform and gives way further out to sponge gardens on the deeper rock, reaching about 12 m. Eastern blue groper are the characteristic residents and are often curious about divers. Wobbegongs rest under ledges, leatherjackets and wrasse feed among the kelp, and moray eels and octopus occupy the cracks. Cuttlefish move in during the cooler months, and Port Jackson sharks appear in winter and early spring. The rocks are also good for nudibranch hunting.

The site's limitations are the same as most of the northern beaches: it faces east and is exposed, the platform is slippery and surge builds quickly with any swell, and sea urchins fill the crevices. Weekend spearfishers and snorkellers share the water. June and August offer the highest proportion of diveable days, when westerly winds flatten the sea. On those days Austinmer is a pleasant, easy-to-reach shallow dive with good facilities on the beachfront and cafés across the road – a good choice for a relaxed second dive or for divers based in the northern suburbs who do not want to drive to Bass Point.

Austinmer is about 20 minutes north of Wollongong on Lawrence Hargrave Drive (or take the Princes Motorway and Bulli Pass/Mount Ousley exits). Park in the beach car park or along Lawrence Hargrave Drive (busy on summer weekends). Walk to the southern end of the beach, past the twin ocean rock pools, and out along the rock platform to a suitable entry point.

Solid-soled booties are recommended for the slippery rock.

The northern Illawarra shore sites face east and are exposed to swell from the north-east round to the south-east; southerly swell wraps around the headlands. Diving is only practical in swell under about 1 m with a low-to-mid tide on the rock platform. North-easterly sea breezes build on summer afternoons, so dive early.

Visibility is typically 5–10 m and drops sharply after rain because of creek and stormwater run-off. Winter (June–August) westerlies give the flattest seas and clearest water. Austinmer is exposed to easterly swell and rips form at the beach ends.

Enter off the platform, descend through the kelp canopy and head seaward to the sponge-covered reef at 8–12 m. Follow the reef south, turn at a third of air and return along the kelp edge to the same exit, timing it between sets.

No regular operator; local divers, snorkellers and spearfishers. United Divers (Fairy Meadow) is the nearest shop.