Sandy Gully Beach is a 500 m strip of sand between two red sandstone headlands at Aireys Inlet, the small Great Ocean Road town best known for the Split Point lighthouse, and it is the southern access to Eagle Nest Reef, the broad limestone reef that runs parallel to this shore for many kilometres. The headlands rise about 20 m and end in rock platforms, and offshore the reef begins a short swim from the sand: an inner limestone reef in 3-5 m suited to beginners in calm water, then the larger main reef structures several hundred metres out in 6-10 m. The rock is the same swell-carved calcarenite as the rest of the Surf Coast, with ledges, holes and gutters whose shaded surfaces are covered in sponges, ascidians, bryozoans and jewel anemones and whose tops carry crayweed and bull kelp.

The fish and invertebrates are those of the Aireys Inlet coast, recorded in detail at Eagle Rock a kilometre south-west: blue-throat and rosy wrasse, herring cale, scalyfin, sea sweep, magpie perch, leatherjackets, Port Jackson sharks, stingarees and banjo sharks, southern rock lobster, octopus, decorator crabs and sea stars, with Australian fur seals visiting from Bass Strait. As a dive site it is quieter and less visited than Eagle Rock and offers a longer, more open reef with fewer people on the beach. The cautions are the standard Surf Coast set and they are not decorative: the beach is bounded by rips that run past the headlands, the swell breaks onto the platforms, and the site is for experienced divers on the rare flat days.

In practice divers at Aireys Inlet check Eagle Rock, Sandy Gully and Sunnymead in turn and dive whichever is calmest, and Sandy Gully, tucked between its headlands, is often the pick in a light north-westerly.

Aireys Inlet is 125 km south-west of Melbourne and 48 km from Geelong via the Great Ocean Road. In the township turn onto Eagle Rock Parade and park at the small parking area at the corner of Kingsley Drive (free). A track leads down to Sandy Gully Beach, a carry of about 150 m.

Enter from the sand opposite Kingsley Drive or from the rock platforms at either end depending on the sea, and swim out to the reef. Exit on the same beach. Eagle Nest Reef's northern entry at Sunnymead Beach is 1.3 km north-east and Eagle Rock Marine Sanctuary 1.4 km south-west.

Only in very calm conditions with minimal wind, flat seas and no swell, with light offshore north-westerly to north-easterly winds. The Scuba Doctor describes a highly hazardous area with deep water, rocks and reefs and a strong rip feeder current and rip running past the headland. Check the water from the parking area before gearing up.

Autumn and early winter give the most chances; visibility 5-15 m when clean. Experienced divers and snorkellers only.

Enter from the beach on a flat day, fin out over the sand to the inner limestone reef at 3-5 m, follow it seaward and along the shore to the main reef structures at 6-10 m, keeping the red headlands as a reference, turn at half gas and return along the inner reef to the beach, avoiding the rips at the platform ends.

No regular commercial operator – dived independently by experienced Geelong and Surf Coast divers and clubs on the rare flat days; Bay City Scuba (Geelong) is the nearest shop. Snorkel tours operate under Parks Victoria licence in summer.