Meet the site
Wreck Reefs take their name from one of the most famous shipwrecks in Australian history. On 17 August 1803 HMS Porpoise, carrying Matthew Flinders back to England after his circumnavigation of Australia, and the merchant ship Cato struck the uncharted reef at night. Wikipedia and Parks Australia record that most of the crews survived on a sandbank; Flinders sailed an open boat to Sydney to organise a rescue, and the survivors were eventually taken off by the Rolla and the schooner Cumberland. Parks Australia records three deaths. The Coral Sea shipwreck register also lists the barque Mahaica (1854), the whalers Jane and Lion (1856) and the schooner Lone Star (1871) as lost here.
The wreck sites of the Porpoise and Cato were found in 1965 by Ben Cropp and Jiri Hrbac after extensive research and, famously, only fifteen minutes of actual diving. Artefacts and structural remains lie among the coral; after more than two centuries, little recognisable structure is likely to remain beyond anchors, cannon, ballast and fittings. Parks Australia notes that the sites are now dive locations. The Wreck Reefs zoning map marks a wreck at the eastern end of the complex.
The reef itself impressed Reef Life Survey divers, who found outstanding visibility, deep blue water, and whitetip and grey reef sharks, black snapper, humpnose unicornfish, Maori wrasse, parrotfish, groupers, tuna, rainbow runner, marlin, Queensland groper and sea snakes, though virtually no sponges or gorgonians.
The sites are protected underwater cultural heritage; nothing may be touched or removed. It suits self-sufficient expedition divers with an interest in maritime history.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Wreck Reef (HMS Porpoise and Cato wreck sites) is recorded as Wreck in Coral Sea. The listed access is boat (multi-day/liveaboard). 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 Wreck Reef (HMS Porpoise and Cato wreck sites) suitable for my certification?
The record lists Advanced 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 Wreck Reef (HMS Porpoise and Cato wreck sites) 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
Whitetip and grey reef sharks, black snapper, humpnose unicornfish, Maori wrasse, parrotfish, groupers (serranids), Queensland groper, tuna, rainbow runner, marlin, sea snakes; few sponges or gorgonians
Location
A 25 km-long reef complex with three cays (Bird Islet, West Islet and Porpoise Cay) about 450 km east-north-east of Gladstone, where HMS Porpoise and the Cato were wrecked in 1803.
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
australianmarineparks.gov.auen.wikipedia.orgoceans1.customer.netspace.net.aureeflifesurvey.comaustralianmarineparks.gov.auRecord updated 27 Sept 2026. Source claims are being reviewed.
