Meet the site
Green Island is a small island off the south coast of Rottnest near Nancy Cove, and one of the island's five marine sanctuary zones. The Rottnest Island Authority says the Green Island Sanctuary Zone protects critical habitat for male Australian sea lions, an endangered species that hauls out on the island. SeaLink's snorkel guide describes the area as a thriving marine ecosystem where you may see sea lions, and recommends it for more adventurous snorkellers in suitable winds.
The reef around the island is limestone with gutters, ledges and seagrass typical of the south coast, and the combination of sanctuary protection and clear southern water supports good fish life. The chance of a sea lion encounter in the water is the main draw, but these are wild, protected animals: keep your distance, do not approach animals on the rocks, and let them choose whether to interact.
No dive-specific description was found, so depths given here are indicative. Green Island suits confident snorkellers and shore divers prepared to cycle a long way with gear, or boat divers exploring the south coast on a calm day.
Combine a visit with Salmon Bay and Little Salmon Bay on the ride back toward the settlement, choosing whichever bay is in the lee. Bring drinking water, as there is none at the beach, and plenty of sun protection for the ride.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Green Island (Rottnest) is recorded as Reef in Rottnest Island. 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.
- 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 Green Island (Rottnest) suitable for my certification?
The record lists Snorkel/Any. 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 Green Island (Rottnest) 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
Australian sea lions (endangered; males), western king wrasse, buffalo bream, sweep, dusky morwong, herring cale, seagrass fauna
Location
Small island and surrounding reef off Rottnest's south coast near Nancy Cove, protected as the Green Island Sanctuary Zone for male Australian sea lions.
Facilities nearby
No facilities at Nancy Cove; nearest toilets at Salmon Bay area or the settlement.
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
rottnestisland.comsealink.com.auRecord updated 27 Sept 2026. Source claims are being reviewed.