Oliver's Reef is a group of small reefs on the Encounter Bay coast between Victor Harbor and Port Elliot. The Marine Life Network describes a variety of small reefs in 8-12 m, with reefs in the wider area ranging from 10 to 20 m, covered in thick kelp. A snorkelling and diving guide places the reef about 150 m offshore from Hayward Street, best on a flat calm day because in rough conditions water moves strongly through holes in the reef, and Diver magazine describes Oliver's Reef as a boat dive with abundant marine life thriving in the currents.

The kelp forest is the dominant habitat, with crevices and holes in the rock beneath. Leafy seadragons are occasionally seen, according to the Marine Life Network, along with bullseyes, leatherjackets, wrasse and morwong, and sea stars and nudibranchs in the crevices. The combination of kelp canopy and small reefs makes for an atmospheric temperate dive typical of the southern Fleurieu.

Divers should confirm the mark with local anglers, clubs or Adelaide shops before going. As with all Encounter Bay sites, the reef is only worth diving after northerly winds with low southerly swell. Oliver's Reef suits Open Water divers comfortable with kelp and some water movement, and photographers seeking seadragons away from the Bluff.

Carry a knife in case of entanglement in kelp or fishing line. A surface marker is essential for the swim or boat pickup, and a compass helps to move between the small reefs in kelp.

Sources differ on access: one guide places the entry at Hayward Street, Victor Harbor, with the reef about 150 m offshore; the Marine Life Network describes access from rocks near Port Elliot; Diver magazine lists it as a boat dive. Confirm the location locally before going. By boat, launch at the Bluff ramp or at Port Elliot/Victor Harbor and use a GPS mark.

By shore, park near the entry point, enter from the rocks on a flat day and surface-swim out with a marker buoy.

Encounter Bay faces south into the Southern Ocean swell that wraps around Kangaroo Island and Cape Jervis, so Victor Harbor sites are the reverse of the gulf coast: they need northerly (offshore) winds. The best days follow several days of northerlies with low southerly swell, when visibility improves and the swell is blown back; any southerly or south-westerly swell over about 1 m, or strong southerly winds, makes most sites undiveable and stirs up particles. Summer and autumn bring the most northerly days, but good windows also occur in winter ahead of cold fronts.

Tidal currents strengthen around the headlands and islands during large tidal movements. Southern right whales visit Encounter Bay from about June to October – keep legal approach distances. Water is a little cooler than in the gulf.

Oliver's Reef needs a flat calm day; in rough conditions water surges through the holes in the reef.

Descend on the largest reef, work around its kelp-covered edge at 8-12 m looking into crevices for nudibranchs and seadragons, then move between neighbouring reefs by compass before returning.

No regular operator; listed by Diver magazine as a boat dive offered by Adelaide shops on Victor Harbor trips.