Meet the site
Grey Crags at Western Bay is rated 6 out of 10 by the Marine Life Network guide. Quartz ridges run parallel to the shore from Seal Rock to Rocky Bay; about 50 m offshore the bottom drops quickly from 5 m to 10 m, then to jagged ridges at 15 m, forming a maze of sand-filled gutters, rock walls and bommies. Lace bryozoa, cup corals, nudibranchs and tunicates fill the crevices, large schools of barber perch hang on the rock faces, and trumpeter, sea sweep, zebrafish, long-finned pike, magpie perch, rock cod and wrasse are common. The guide advises good air monitoring and navigation for the longer current-assisted swims. 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.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Grey Crags (Western Bay) is recorded as Shore/Rock Platform in Tasmania North & North-West. The listed access is shore. Confirm the actual meeting point, route and permission to visit; a map pin does not establish any of these.
Topics flagged by the stored research
These are questions prompted by the existing notes, not a verified or complete hazard assessment.
- Current and timing
- Ask how the operator assesses the current window for the actual route. Historical tide notes are not a departure instruction.
Historical access notes exist for this record, but have not been independently verified for current use. Request current directions from the operator or site manager rather than following an old entry description.
Questions, answered
Is Grey Crags (Western Bay) suitable for my certification?
The record lists Advanced Open Water. That does not establish suitability for every route or day. Share your training, recent experience and equipment needs with the operator and ask about the specific proposed dive.
Can I book Grey Crags (Western Bay) through YouDive?
YouDive is an independent research directory. Contact an operator directly to confirm whether it currently runs the trip, the inclusions and the booking terms.
What you might see
Barber perch, trumpeter, sea sweep, zebrafish, long-finned pike, magpie perch, rock cod, wrasse, lace bryozoans, cup corals, nudibranchs, tunicates
Location
Quartz ridges parallel to the shore from Seal Rock to Rocky Bay near Boat Harbour, dropping from 5 m to 10 m about 50 m out then to jagged ridges at 15 m.
Facilities nearby
Sisters Beach: general store, toilets, boat ramp, picnic areas. Boat Harbour Beach: surf club change rooms, toilets, kiosk (seasonal). Wynyard for all services; no confirmed local air fills.
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
marinelife.org.auRecord updated 26 Sept 2026. Source claims are being reviewed.