Cunningham Bay is the little-visited pair of beaches at the southern end of the Phillip Island Grand Prix circuit, reached down a track from the end of Gap Road, and it is one of the south-coast shore dives that Ian Lewis documented in Shore Dives of Victoria. Two narrow sand platform beaches – The Gap to the east and Racetrack to the west – sit under 40 m bluffs, and offshore there are, in Scuba Doctor's description, multiple reefs to explore in the 5 to 10 metre deep water. The reefs are basalt like the rest of this coast, arranged as a series of platforms and low ridges separated by sand, running out to about 12 m.

Their tops carry kelp and coralline algae; their sides and undercuts are lined with encrusting sponge, ascidians and zoanthids; and the sand gutters between them collect shells, rays and flathead. The fish community matches YCW Beach a kilometre east – wrasse, morwong, sweep, leatherjackets, zebrafish, boarfish under ledges and Port Jackson sharks in the gutters in cooler months – and crayfish and abalone occur in the cracks. What distinguishes Cunningham Bay is its seclusion and its partial shelter.

The headlands and bluff line give some protection from south-westerly swell, so on a day when the more open beaches are marginal this bay can be workable, and because the access involves a real climb it is rarely used by anyone except surfers and the occasional club. That access is the price. The bluff track is steep, the beaches are small at high tide, and the climb back with wet gear is the hardest part of the day.

Combined with the racetrack noise on event days it will never be a popular site, but it offers a quiet, structured reef dive with good relief for divers prepared to earn it, and it is a sensible alternative when Smiths, YCW or Sunderland Bay have too much swell.

From Cowes take Ventnor Road then Back Beach Road, and turn south into Gap Road which runs down the eastern side of the Grand Prix circuit to a small parking area at its southern end (about 10 km, 12 minutes from Cowes). A track descends the 40 m bluff to the narrow beaches – allow 10 minutes each way with gear and expect a steep climb back. The Gap beach is to the east and Racetrack beach to the west; both give access to the reefs in 5–10 m offshore.

YCW Beach is 1 km to the east and shares the same road network.

Faces south, so best dived with an offshore northerly wind and small swell at high tide; Scuba Doctor notes that the coastal geography gives some protection from south-westerlies, which makes Cunningham Bay a slightly better bet than Smiths or YCW when the swell has a westerly component, but a southerly swell over a metre still breaks across the reef. Early mornings before the sea breeze are best. The bluff track is slippery after rain.

Diveable year-round on the right day; autumn northerlies most reliable. Motor-racing event days bring road closures around the circuit.

Enter from whichever beach is calmer, swim out over the sand to the first reef at 5 m and work seaward through the reefs to 10–12 m, keeping the bluff on one shoulder. Turn at half gas, return through the shallower reef closer in, and exit on the same beach. Save energy for the climb.

No dive shop or dedicated dive charter is based on Phillip Island. Sites are dived by Melbourne clubs (VSAG, Melbourne University Underwater Club, Frankston/Peninsula clubs) and private boats launched at Newhaven or Rhyll; Mornington Peninsula shops (Dive Victoria Group, Portsea; The Scuba Doctor, Rye) run occasional Phillip Island days. Ocean Adventures Phillip Island (Cowes) runs seal-snorkel tours only.