Meet the site
The Sponge Garden, on the north-eastern side of Sisters Island, is rated 7 out of 10 by the Marine Life Network guide. The reef starts near shore and stretches more than 100 m from the island, with jagged bommies covered in red, orange, pink and yellow sponges, lace bryozoans, gorgonians, nudibranchs, tunicates and hydroids over a thick understorey of pink coralline algae. Barber perch, leatherjackets, wrasse and southern hulafish are common; crayfish and abalone are sparse. The guide recommends drift diving with a competent, alert boat operator. 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.
The Sponge Garden (Sisters Island) is recorded as Reef 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.
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 Sponge Garden (Sisters Island) 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 The Sponge Garden (Sisters Island) 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
Sponges (red, orange, pink, yellow), lace bryozoans, gorgonians, nudibranchs, tunicates, hydroids, coralline algae, barber perch, leatherjackets, wrasse, southern hulafish
Location
An extensive reef of jagged bommies covered in colourful sponges on the north-eastern side of Sisters Island, stretching 100 m-plus from the island.
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.