Meet the site
Mushroom Rock is Hamelin Bay's closest reef dive to shore. Marinelife.org.au describes it as a 6-15 m site about 200 m - a moderately stiff swim - from the boat ramp, with a small overhang, narrow channels on its western side and good fish life. The overhang on the north-west side hosts colourful invertebrates, and the fish list includes buffalo bream, old wives, pullers, scalyfin, morwong, herring, wrasse, leatherjackets and cuttlefish, with gorgonian fans.
The rock is part of the cluster of limestone features at the southern end of the bay along with Peak Island and Mushroom Reef, which lies between them. The combination of overhangs, channels and gorgonians gives it more colour than the sandy wreck sites, and it can be reached without a boat by fit divers.
It suits Open Water divers comfortable with a surface swim and moderate depth, and it pairs well with a snorkel with the stingrays at the ramp afterwards. Watch for boats using the ramp, and fly a flag during the swim out and back.
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.
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 Rock is recorded as Reef in Margaret River & Augusta. The listed access is shore or 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.
- 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 Rock 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 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
Buffalo bream, old wife, puller, scalyfin, morwong, herring cale, western king wrasse, leatherjackets, cuttlefish, gorgonians, colourful invertebrates
Location
Rock and reef about 200 m from the Hamelin Bay boat ramp with a small overhang, narrow channels on its western side and good fish life in 6-15 m.
Facilities nearby
Hamelin Bay boat ramp, holiday park and kiosk.
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.
