Twin Reefs is the pair of reefs off the rock platforms midway along the Bunurong Coastal Drive, and it is where Parks Victoria's park description places the groups of Port Jackson sharks resting under the ledges that the park is known for, with rock lobsters and zebrafish around the rocks. It is the most exposed of the Bunurong shore dives and the one most often done by boat or by experienced platform divers. The two reefs are outcrops of the same layered Cretaceous sandstone as the shore, standing a short way off the platform with gutters between and around them, their tops in a few metres of water and their outer faces dropping to 12–15 m.

The undersides of the reefs are extensively undercut, and it is in those low, wide ledges that the Port Jackson sharks pack together in winter and spring, sometimes a dozen in a row, alongside crayfish, abalone, draughtboard sharks and bullseyes. Blue-throat wrasse, zebrafish, sweep, morwong and leatherjackets work the reef tops and gutters, the walls carry sponges, ascidians and bryozoans, and sea stars and feather stars are abundant. The gutters open onto sand where stingarees, flathead and occasional eagle rays lie.

Being offshore, the reefs feel the swell before anything else on this coast and the gully entry from the platform is only safe at high tide on a flat northerly day; the surge in the gutters between the reefs is considerable even then, and Parks Victoria's warnings about currents, undertows and large unexpected waves are most relevant here. On the right morning, however, Twin Reefs offers the best shark-and-cray ledges on the Bunurong coast in a no-take park, and it is a fine boat dive out of Inverloch for those who can time the Anderson Inlet entrance.

From Cape Paterson take the Bunurong Coastal Drive east about 4 km to the Twin Reefs car park and lookout (a whale-watching vantage point); from Inverloch it is about 9 km west. A track descends to the platform – allow 5–10 minutes with gear over rock. Enter through a gully at high tide when the platform is covered and swim out to the reefs, which lie a short distance offshore; exit the same way.

Boat divers launch at the Inverloch ramp on Anderson Inlet and run out through the entrance – tide- and bar-dependent – about 8 km west.

The Bunurong coast faces south-west into Bass Strait and is a surf coast; shore diving is only possible on a northerly or north-easterly wind with swell under about 1 m, at or near high tide for depth over the platforms, and preferably early in the morning. Parks Victoria warns of strong currents and undertows, large unexpected waves and sudden swell changes, so watch the forecast for the day, not just the morning. Visibility is best in autumn after settled weather and drops for days after a south-westerly blow.

Year-round in principle; autumn most reliable.

Enter through the gully at high tide, swim out to the nearer reef and work around it with the rock on one shoulder, checking under the ledges for Port Jackson sharks and crayfish at 6–12 m; cross to the second reef only in flat conditions. Turn at half gas, return to the platform and exit through the same gully while there is still water over it.

No dive shop on the Bunurong coast; sites are dived by independent divers and Melbourne/Gippsland clubs (SEADS – South East Australian Dive Society, Dive La Trobe, VSAG). Nearest air fills in Melbourne's south-east or by arrangement in the Latrobe Valley.