The cliffs on the eastern side of the Port Arthur entrance run south towards Budget Head and Cape Pillar, and the Marine Life Network guide describes the reef at their base in 5-30 m. It is a narrow band of rocky reef that gives way to a flat sandy bottom scattered with boulders, and the guide notes that the marine life is shaped by surge – the shallows are dominated by tough brown algae and kelp rather than delicate invertebrates. Deeper down, the boulders on the sand provide shelter for fish and rock lobster and host sponges and other invertebrates.

Common fish include wrasse, leatherjackets, magpie morwong and banded morwong, and rays forage on the sand. This is not a showpiece site but a useful option for boats launching from Port Arthur, which is often calm when the Eaglehawk Neck coast is rough. The scenery above water, with high dolerite cliffs, is impressive, and the area sees few divers.

Combine it with a shallower dive inside Port Arthur, such as Point Puer or Carnarvon Bay, for a sheltered second dive. Details come from an older guide; expect to explore. For divers staying at Port Arthur or Nubeena, the eastern cliffs make a convenient boat dive without the long run to the Tasman Sea coast.

Wildlife on the way often includes fur seals, dolphins and seabirds, and the Port Arthur Historic Site is visible from the water on the return trip. A boat with a sounder and a local skipper will find the best patches of boulder reef.

Boat access only. Launch at the Port Arthur boat ramp (Carnarvon Bay, off Safety Cove Road, 1.5 hours' drive from Hobart via the Arthur Highway) or at Nubeena, then head south out of Port Arthur and along the eastern shore towards Budget Head and Cape Pillar. Run time is roughly 10-20 minutes depending on the drop point.

Go Dive Tasmania sometimes launches at Port Arthur when the east coast is rough.

The Port Arthur coast faces south into Storm Bay and is closed by southerly and south-easterly swell, which also leaves surge on the shallow reef; the Marine Life Network notes marine life here is surge-affected. Northerly and westerly winds give calm water. Because Port Arthur launches are sheltered, operators use this area when easterly weather blows out the Eaglehawk Neck sites, but big southerly groundswell closes both.

Descend at the base of the cliff, follow the narrow reef to its seaward edge at 20-30 m and look through the boulders on the sand. Return along the reef in shallower water and ascend in the lee of the cliff.

No regular operator; Go Dive Tasmania may use Port Arthur-side sites when launching from Port Arthur; private boats.