Meet the site
The Thumbs are a group of distinctive rock formations on the east coast of the Tasman Peninsula, named for their shape above the water, with steep walls dropping into deep water below. Go Dive Tasmania lists them at 15-40 m or more, with vertical walls and sponge gardens, suitable for Advanced or Deep divers. The Marine Life Network guide places the Thumbs north of Fortescue Bay and describes a sharp wall drop-off in 30-35 m with seaweed on the upper sections and sea whips deeper down, along with butterfly perch and real bastard trumpeter. The Divers Alert Network's Tasmania feature groups the Sisters and the Thumbs together as the advanced dives of the area, around 40 m deep and notable for sponge gardens, surge and currents that are impossible to predict. The top of the formation is a kelp-covered platform where fur seals may appear; the real interest is on the wall, where invertebrate cover becomes progressively richer below 20 m. Sponges in yellow, orange and red, fields of sea whips and gorgonians, and the endless schools of butterfly perch that characterise this coast make it a striking dive in good visibility. It is a deep, exposed site for experienced divers only, and because depth limits bottom time it is typically a single focused descent rather than an exploration. The site is a good choice for divers who have done the Waterfall Bay caves and want the deep-water gardens without the long run to the Hippolytes. Operators will only go in settled conditions; be prepared for last-minute changes.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
The Thumbs is recorded as Pinnacle/Bommie in Tasman Peninsula. The listed access is boat (day trip). 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.
- Water movement
- Ask how swell and local exposure affect the proposed entry, exit and route.
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 The Thumbs suitable for my certification?
The record lists Deep/Advanced + experience. 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 The Thumbs 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
Sea whips, gorgonians, sponges, jewel anemones, butterfly perch, real bastard trumpeter, boarfish, banded morwong, southern rock lobster, fur seals
Location
Distinctive rock formations with a sharp wall drop-off on the east coast of the Tasman Peninsula north of Fortescue Bay.
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
godivetas.com.aumarinelife.org.audan.orgeaglehawkdive.com.auRecord updated 26 Sept 2026. Source claims are being reviewed.