The Kiryo Maru I is Rottnest's most recent historic-era wreck and one of its hardest to dive. She was a 35.7 m, 200-ton Japanese steel tuna longliner. At about 3 am on 3 August 1984, heading for Fremantle, she lost propulsion and went hard aground on the reef shelf beside Cathedral Rocks at the West End. Salvage attempts failed in the Southern Ocean swell, and she was broken up where she lay.

The main part of the wreck lies under the breakers on the reef shelf and is effectively undiveable, but a scattered debris field extends into 2-9 m around Cathedral Rocks. Visibility here is typically 5-10 m because of the white water. The Rottnest Island Authority notes the wreck lies about 50 m offshore, and marinelife.org.au warns that the reefs at the entrance to this bay have claimed tuna boats.

It is really a curiosity for divers who have reached Cathedral Rocks on one of the two or three days a year when it is diveable. The surrounding West End reefs are part of the West End Demersal Sanctuary Zone, and Australian and New Zealand fur seals and sea lions are commonly seen around the rocks. Because the wreck is less than 75 years old it is not covered by historic shipwreck protection, but it is within the Rottnest Island Reserve. Anyone planning a West End trip should read the forecast for several days beforehand and have a sheltered alternative in mind, such as the Transit Reef wrecks or Roe Reef on the north-east side.

The West End is the far end of Rottnest, roughly 30 km from Fremantle and 1-2 hours by charter boat. Private boats run along either coast to Cape Vlamingh and approach Cathedral Rocks through the sheltered eastern reef passage into (Rottnest's) Eagle Bay, where there is anchoring. Only attempt in near-flat conditions.

The Cathedral Rocks area can also be viewed from the Cape Vlamingh boardwalk.

The main wreck site lies under the breakers and divingwawrecks gives a limit of under 0.5 m of swell - so only on the rare days of glassy calm, usually after several days of easterlies in summer. Southern Ocean swell wraps around the West End almost all year. General pattern at Rottnest: summer brings calm morning easterlies followed by a strong south-westerly sea breeze from late morning, so dive early; winter brings north-westerly fronts and large swell, with clear, calm spells between them.

Check the Bureau of Meteorology coastal forecast for swell height and period before committing.

Anchor in the lee of Cathedral Rocks, swim to the debris field in 2-9 m and explore scattered plates and machinery, staying well clear of the break zone; combine with the Cathedral Rocks caverns if conditions allow. Agree a turn pressure before descending (half gas, or a third where current is likely), carry a DSMB, and make a 3-minute safety stop at 5 m.

No regular operator; very occasionally visited on Perth charter trips that reach the West End for Cathedral Rocks or Shark Cave on exceptional days.