Meet the site
Mushroom Reef is a small site between Mushroom Rock and Peak Island. Marinelife.org.au describes an 8 m reef with a narrow crevice cutting through the island, packed with marine life, which is good in suitable weather but too narrow and dangerous in swell.
The crevice concentrates fish and invertebrates in the way that narrow limestone channels do: pullers, scalyfin, wrasse and bream sheltering in the walls, with sponges and encrusting life in the shaded parts. It is a short, interesting add-on to the Toba wreck and Mushroom Rock, all within a few hundred metres of each other.
The risk is surge. Even modest swell accelerates water through narrow gaps, and a diver caught in the crevice can be pushed against the rock. Treat it as a flat-calm-only site and do not enter the crevice unless conditions are benign.
Published detail is limited, so the position and depths are indicative.
Hamelin Bay was a timber port from the 1880s, when a jetty built in 1882 and extended in 1898 served M. C. Davies' milling operations. It was notorious for wrecks in bad weather because it is exposed to the north-west gales of winter storms; the 22 July 1900 storm alone wrecked several ships, and only the old jetty piles remain today. The bay is now a recreation zone in the Ngari Capes Marine Park, and every wreck in it older than 75 years is protected. Combine it with Mushroom Rock and the Toba on the same outing, all within a few hundred metres of the ramp.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Mushroom Reef is recorded as Reef in Margaret River & Augusta. 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.
- Other water users
- Ask about vessel activity, exclusion areas and the agreed surface arrangements.
- 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 Mushroom Reef suitable for my certification?
The record lists 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 Mushroom Reef 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
Pullers, scalyfin, western king wrasse, buffalo bream, old wife, sponges and invertebrates on crevice walls
Location
Reef in about 8 m between Mushroom Rock and Peak Island in Hamelin Bay, cut by a narrow crevice through the island that is packed with marine life.
Facilities nearby
Hamelin Bay boat ramp and holiday park.
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.
