North West Rocky Cape is a reef that rises from over 20 m to about 10 m, about 2.6 km from the Rocky Cape ramp. Michael McFadyen describes gutters running east-west along the bottom, small boulders that provide habitat for smaller fish, a gutter on the northern section worth exploring, and a reef that turns north as you head east into the current. He recorded leatherjackets, wrasse, schools of seapike, sponges and small gorgonians, with 20 m visibility and 18.8 °C water, and rated it less impressive than the other Rocky Cape and Sisters Beach sites but a nice dive nonetheless. Local divers typically combine two or three Rocky Cape and Sisters Island sites in a day, choosing the side of the cape that suits the wind and the state of the tide.

The Rocky Cape and Sisters Island area is, in the Leven Scuba Club's words, the best collection of dive sites on the north-west coast. The quartzite of Rocky Cape - some of the oldest rock in Tasmania - forms gutters, ledges, caves and bommies, and the tidal flow along Bass Strait keeps sponges, gorgonians, sea pens and bryozoans well fed. Michael McFadyen, diving here in February 2008, recorded 18-19 °C water and 20-25 m visibility, figures that surprise divers used to the east coast.

Rocky Cape National Park also protects Aboriginal cave sites and coastal heath above the water, and a Parks Pass is required for vehicles. The nearest hyperbaric chamber is the Royal Hobart Hospital, about four hours' drive away, so conservative profiles and oxygen on the boat are essential.

Rocky Cape National Park is off the Bass Highway between Wynyard and Stanley, about 30 minutes west of Wynyard and 1 hr 15 min west of Devonport (Spirit of Tasmania terminal). A Parks Pass is required. Boats launch at the Rocky Cape boat ramps (the western ramp at Mary Ann Bay suits boats up to about 5 m), Sisters Beach or Boat Harbour; ramps are shallow and weedy at low tide, so a 4WD tow vehicle helps.

Run about 2.6 km from the Rocky Cape boat ramp (McFadyen: 40 50 37.8 S, 145 30 04.2 E).

The north-west coast faces Bass Strait: north-westerly to north-easterly winds and westerly swell make it rough, while southerly winds blow offshore and give flat seas - light airs and sunny days are relatively common from January to April. Easterly gales are common in the warmer months and close the eastern faces of Rocky Cape and Sisters Island. Tidal streams run along the coast (eastward on the flood), and several boat sites are only comfortable around slack water.

Current runs along the reef; plan the dive into the current.

Descend onto the reef, follow the east-west gutters into the current and check the northern gutter, then turn and drift back. Turn the dive at half gas (thirds where current or overhead sections are involved), deploy an SMB before surfacing for the live-boat pick-up, and complete a 3-minute safety stop at about 5 m where depth allows.

No confirmed commercial dive operator on the north-west coast as of 2026 (older guides mention dive services in Wynyard and Devonport - verify). Sites are dived mainly by the Leven Scuba Club (Ulverstone), other north-west club members and visiting divers with their own boats; Tasmanian Divers (Launceston) runs occasional northern trips.