Meet the site
Garden Island forms the western wall of Cockburn Sound: about 10 km long and 1.5 km wide, joined to Point Peron by a causeway and occupied by HMAS Stirling, the Royal Australian Navy's largest base. Because of the base, public access is tightly controlled. The causeway is closed to the public unless entry is sponsored by the military, and visitors by sea are restricted to private boats using moorings and anchorages in designated areas, during daylight hours.
Within these limits the island's sheltered northern and eastern bays are popular with boaters for swimming and snorkelling. The limestone reefs and seagrass around the island support the same life as the rest of the Cockburn Sound margin: buffalo bream, wrasse, sweep, herring cale, cuttlefish, octopus and rays, with dolphins common. The island's western side faces Five Fathom Bank, and offshore reefs such as Challenger Rock lie near its northern tip.
No dive-specific guide to Garden Island was found, and this record exists mainly to document the access restrictions. Divers planning a visit must check the current Defence boating rules, respect prohibited zones around naval facilities, leave before the daylight curfew and keep clear of warships and Defence vessels.
For most divers, the nearby Point Peron, Shoalwater and Five Fathom Bank sites give better and more accessible diving. Garden Island is best treated as a snorkel stop for private boats.
Boats that do visit should carry a copy of the current rules, anchor only in sand, and plan their departure well before the curfew, allowing for the run back across Cockburn Sound against the afternoon sea breeze.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Garden Island (Defence restricted) is recorded as Island in Perth. 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.
- 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 Garden Island (Defence restricted) 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 Garden Island (Defence restricted) 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, wrasse, sweep, herring cale, cuttlefish, octopus, rays, bottlenose dolphins, seagrass fauna
Location
The 10 km long island forming the western side of Cockburn Sound, occupied by HMAS Stirling (Fleet Base West); public access is restricted to daylight boat visits to designated areas.
Facilities nearby
None for the public on the island; launch at Point Peron, Rockingham or Woodman Point.
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
en.wikipedia.orgdefence.gov.auRecord updated 26 Sept 2026. Source claims are being reviewed.
