Pyramid Rock is the tall basalt stack at the end of Pyramid Rock Road, one of Phillip Island's landmark views, and underwater it is described by Scuba Doctor as an epic shore dive with steep kelp-covered walls, boulders and ledges. The headland and stack are columnar basalt, and below the waterline the columns continue as near-vertical faces dropping to 12–15 m on the seaward side, broken by ledges and collapsed blocks. The upper faces are dense with kelp; below the kelp line the walls are coloured with sponges, zoanthids, small gorgonians, sea stars and molluscs.

Fish life is as good as anywhere on the island's shore: kingfish pass the outer point in summer, and residents include morwong, pike, wrasse, boarfish, old wives, bullseyes in the shaded ledges, leatherjackets, catsharks and Port Jackson sharks. The eastern side of the headland is where the dive begins and ends – a shallow, comparatively protected cobble beach at 2–5 m with weed and boulders that is itself a good snorkel on a flat day. The problem is getting there.

The boardwalk from the car park to the lookout is long, the descent to the cobble beach is steep, and the site faces the open strait, so Scuba Doctor states plainly that boat diving is recommended for safety and that the shore dive requires strength, endurance, patience and good sea sense. Done from a boat out of Newhaven it becomes a straightforward and very scenic wall dive, with the George Kermode dredge wreck 2 km to the east and the Golden Bommies 2.5 km south giving a full day. Done from shore on a rare flat, windless morning it is a memorable outing for fit, experienced divers who accept the carry.

Either way it is one of the most dramatic pieces of shallow topography on the island.

From Cowes take Ventnor Road then Back Beach Road to Pyramid Rock Road and follow it south to the car park at its end (about 12 km, 15 minutes). From the car park it is a long walk along the boardwalk to the lookout – several hundred metres – and then a scramble down to the cobble beach on the eastern side of the headland, which is the only practical entry. Expect a 15–20 minute gear carry each way; many divers do it as a boat dive from Newhaven (about 30 minutes west along the coast) instead.

Boats anchor in sand off the eastern side of the rock.

This is the exposed south coast of the island facing straight into Bass Strait; the shore dive is only possible early in the morning on a day with calm seas and no wind, or steady offshore northerly winds, and at high tide. Any south-westerly or southerly swell above about 0.5 m breaks over the cobbles and makes the entry dangerous. Scuba Doctor also warns that strong easterlies spoil the eastern beach.

Look for a run of two or three days of northerlies, check the Pyramid Rock swell forecast, and go at first light before the sea breeze. Visibility is best in autumn and on clear winter days. Boat divers have more latitude but still need swell under 1 m.

From the eastern cobble beach, swim out along the base of the headland and follow the wall of the rock seaward, descending progressively to 12–15 m at the outer face. Keep the wall on your right going out, explore the boulders and ledges at the base, turn at half gas or when surge increases, and return along the wall with the rock on your left, finishing in the shallow kelp of the cobble beach. Boat divers can start at the outer face and finish under the boat.

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.