Meet the site
Simmos Reef at Shag Rock is described by Michael McFadyen as a very good dive site. The bommie is shaped like a figure 6 with its top pointing north, rising from about 25 m of sand to about 4 m, with more than 20 m on the northern side and kelp on the upper sections. He recorded red sponges, lace coral, bryozoans and gorgonians, lemon-coloured sea pens, dumpling squid and cuttlefish, red morwong, seapike, leatherjackets, numerous small long-snouted boarfish and several starfish species, with 25 m visibility and 18.7 °C water in February.
The Marine Life Network guide describes what appears to be the same site as Elephant Shark (Shag) Rock, rated 5.5 out of 10: an arc of rock spires with bommies rising almost sheer from 10-18 m, large cup sponges and sea fans, and magpie perch, wrasse, leatherjackets, banded morwong, rainbowfish, scalyfin, barber perch and schools of bastard trumpeter and long-finned pike. 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.
Simmos Reef (Shag Rock) is recorded as Pinnacle/Bommie in Tasmania North & North-West. The listed access is boat. 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.
- Other water users
- Ask about vessel activity, exclusion areas and the agreed surface arrangements.
- Planned depth
- Confirm the intended route and training requirements; the recorded maximum is not a target.
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 Simmos Reef (Shag Rock) 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 Simmos Reef (Shag Rock) 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
Red sponges, lace bryozoans, gorgonians, sea pens, dumpling squid, cuttlefish, red morwong, seapike, leatherjackets, long-snouted boarfish, bastard trumpeter, long-finned pike, magpie perch, starfish
Location
A figure-6-shaped bommie at Shag (Elephant Shark) Rock off Sisters Beach, rising from 25 m sand to about 4 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
michaelmcfadyenscuba.infomarinelife.org.auRecord updated 26 Sept 2026. Source claims are being reviewed.