South Rock is the deep, current-swept site of Norfolk's dive list. Oceanatik describes 'a beautiful rock pinnacle dropping to 40 meters of water' with strong currents and depth that make it 'an advanced level dive'. The Marine Life Network describes Phillip Island's diving as 15–40 m, with South Rock offering deep drop-offs.

Phillip Island lies about 6 km south of Norfolk and is a national park, famous for its eroded red and purple soils and recovering vegetation. Its surrounding waters take the full force of the ocean currents moving past the Norfolk Ridge, and a pinnacle in that flow gathers fish. Oceanatik records 'big and small marine fish in abundance' with black corals, hard and soft corals, anemones, sponges and sea fans on the rock.

The black coral is a sign of depth and current: these colonial animals grow where plankton-rich water flows past, usually below 20 m. Kingfish, trevally and Galapagos sharks are the likely larger fish, although the sources do not list species for this site.

This is a site for experienced divers with deep training who are comfortable with strong current and open-water ascents from a small boat. It is the longest run from Kingston Pier of the regular sites and is exposed to southerly swell, so it is dived only on calm days. Nitrox, if it can be arranged, is worth using on a profile like this. The exact position of the pinnacle is not published; the coordinates given are for Phillip Island's southern side and are approximate.

Norfolk Island is about 1,450 km east of Brisbane; flights run from Sydney and Brisbane (about 2.5 h; check the current carrier). A hire car is essential. Norfolk has no harbour: Norfolk Island Diving's open boat is lowered by crane from Kingston Pier (south coast) or Cascade Pier (north-east coast), whichever is in the lee of the day's wind, and divers board from the pier steps once it is in the water.

For Phillip Island the boat launches at Kingston Pier and runs about 6 km south past Nepean Island, roughly 15–20 minutes. Phillip Island is part of Norfolk Island National Park; landing requires a permit and is not part of the dive.

Norfolk's south coast, including Kingston, Nepean Island and Phillip Island, faces the prevailing south-east trade winds and southerly swell, which are strongest from May to September. A south-easterly over about 15 knots or a southerly swell above 1.5–2 m makes the boat launch at Kingston Pier unworkable and the southern sites rough; they are dived on northerly or light-wind days, often in summer. Surge is felt in caves and gutters with any swell.

Visibility is typically 20–40 m and can exceed 40 m in winter. There are no stingers, and cyclones rarely reach this far south, though ex-tropical lows can bring big seas in summer and autumn.

Descend quickly on the up-current side of the pinnacle to 25–30 m, stay close to the rock to shelter from the current, and look for black coral, sea fans and schooling fish. Only deep-trained divers should go towards 40 m. Work up the pinnacle and ascend under an SMB for pick-up.

Nitrox (EAN28–32) recommended for the 25–30 m sections; below 30 m requires deep training; plan conservatively given the absence of a chamber.

Norfolk Island Diving (local instructor James and divemaster Mitch Graham) – small open boat craned in at Kingston or Cascade Pier depending on wind; runs part-time, mostly weekends, so book ahead by email (norfolkislanddiving@gmail.com).