Cape Raoul is the southern tip of the Tasman Peninsula's western arm, famous for its spectacular organ-pipe columns of dolerite and a 300 m clifftop walk. The Marine Life Network guide lists Salters Point near Cape Raoul as a boat dive of 8-28 m, describing a volcanic bluff with kelp and ridges of boulders, and recording crayfish, sea tulips and butterfly perch. The ridges run down the slope like spokes, creating gutters and overhangs where rock lobsters shelter.

Sea tulips – stalked ascidians that sway on the reef – are a notable feature; they are the same animals that spotted handfish use for spawning in the Derwent estuary. Schools of butterfly perch hang over the deeper ridges, and wrasse, leatherjackets and morwong are common on the kelp-covered upper reef. Seal Rock, a fur seal haul-out near Cape Raoul, can be seen from the cape walking track and from cruise boats, so seals may appear during a dive.

The site is rarely dived and documentation is limited, but its setting is magnificent. It suits experienced divers with their own boat and good local knowledge. Remember the seal-watching rules: vessels must keep at least 50 m from seals and 100 m during the November-December pupping season, and slow down within 200 m of a colony.

Cape Raoul is best combined with other western-side sites such as Wedge Island or Fosters Rock on a calm day. The run around the cape passes some of the finest coastal scenery in Tasmania, and even on a day when conditions do not allow a dive, the boat trip under the columns is worth making.

Boat access only. Launch at Port Arthur (Carnarvon Bay ramp) or Nubeena and run south-west around Cape Raoul, roughly 20-30 minutes depending on the ramp and sea. Cape Raoul itself is reached on land by a 7 km walking track from Stormlea Road off the Nubeena Road, but there is no dive access from the track.

The exact mark for Salters Point is not published; use a sounder to find the ridges.

Cape Raoul faces south into the Southern Ocean and is exposed to all southerly swell. Dive only on calm days with northerly or light westerly winds and swell under about 1 m. Seal Rock nearby holds a fur seal colony; observe vessel approach distances.

Currents off the cape can be moderate on spring tides. Seas can rise quickly when a south-westerly change arrives, so keep an eye on the forecast.

Descend on the kelp-covered slope, follow a boulder ridge down to 20-25 m, then zig-zag back up along the next ridge looking for crayfish and sea tulips. Ascend in the kelp at the bluff.

No regular operator; private boats from Port Arthur or Nubeena. Seal-watching cruises (Pennicott) pass Cape Raoul.