Jack's Patch is an offshore dive and snorkel site located off Salmon Bay on the south side of Rottnest Island. This open-water spot is renowned for its clear waters, deep ledges, extensive swim-throughs, and a large cave that beckons experienced snorkellers and divers. Grey nurse sharks are frequent visitors, and the site teems with western rock lobsters (crays) and colourful nudibranchs. The patchy reef structure gives the site its name, creating a maze-like underwater terrain that rewards exploration.
Jack's Patch
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Wave Height 0.4 mSwell Period 12 sWind Speed 0.6 knPrecipitation 0.8 mmTidal Phase ebb
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© Peter SouthwoodThe spot
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Community contribution: submitted by Daniel
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Moderate risk: Open ocean swell
Jack's Patch is an exposed open-water site off Salmon Bay, susceptible to southerly swells that can create surge and reduce visibility.
Moderate risk: Strong currents
Tidal flows around the reef ledges and swim-throughs can be strong, especially during tide changes.
Moderate risk: Deep water
The site drops to around 27 metres at its deepest point, requiring good buoyancy control and confidence in deeper water.
Low risk: Boat traffic
Located offshore and accessed by boat; snorkellers must be vigilant for dive vessels and other watercraft in the area.
Wildlife Guide
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Gallery
1 photo from the community
Getting in
Boat
Entry
Jack's Patch is located off the south coast of Rottnest Island, near Salmon Bay. It is not accessible from shore — you must book a boat charter or guided snorkel/dive tour from Rottnest Island or Fremantle. Ferry services from Fremantle or Perth to Rottnest Island arrive at Thomson Bay, from where local tour operators can take you to the site.
Parking & facilities
Parking is available at the Rottnest Island ferry terminals in Fremantle (B-Shed or Victoria Quay) for day trippers. On Rottnest Island, bicycles and the Hop-on-Hop-off bus are the primary modes of transport — no car parking is available on the island itself.
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No site-specific fee, but a Rottnest Island Admission Fee (around $15–20 per adult) applies to all visitors. Snorkel/dive boat tours typically cost $100–$200 per person.
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About this data
- Conditions last evaluated
- Spot data last updated
- Data sources
- Open-Meteo (marine & weather conditions), tide predictions via UTide, community contributors (descriptions, hazards, marine life).
- License
- Spot content licensed under CC BY-SA 4.0. How's the Spot is open source.
Weather & swell ┬╖ Open-Meteo marine & weather APIs Tides ┬╖ UTide harmonic analysis Sea & safety ┬╖ community reports