The Macedon is the most intact of the old iron wrecks at Rottnest and the core of the popular 'Three Wrecks' dive on Transit Reef. She was a British-built iron screw steamer, 63 m long, recorded as 532 tons by divingwawrecks and 562 tons by the WA Museum trail guide. On 21 March 1883 she left Fremantle for the Kimberley carrying about 50 passengers, some 40 horses, mail, specie and general cargo, including a survey party whose members included future Premier Walter James. With dignitaries aboard, the master took her close along the Rottnest shore for the view and put her onto West Transit Reef, holing the hull. Nobody died, but the ship could not be saved and rough weather broke her up in place.

Today the hull sits upright on the reef in 3-7 m, running for nearly 50 m, with ribs and gunwales still standing and the boiler of her 100-horsepower engine clearly recognisable. Coal and fragments of bottles lie inside the hull. The surrounding limestone reef has small caves and overhangs, and the Denton Holme lies only a few tens of metres away, so most divers treat the two as one dive, with the scattered Janet about 80 m to the east.

Because it is shallow, sheltered and close to the settlement, the Macedon is the first wreck most Perth divers ever see, and it is one of the best introductions to historic wreck diving in the state: easy to navigate, with plenty of structure and good fish life. Buffalo bream and sweep school over the hull, western rock lobster hide under plates, and bullseyes gather in the shadows. The site is inside the Kingston Sanctuary Zone and is a protected historic shipwreck, so nothing may be touched or taken. It suits Open Water divers, snorkellers on flat days (parts of the hull can be seen from the surface) and photographers wanting wide-angle wreck shots in good light.

Rottnest lies about 18 km west of Fremantle. Perth charter boats (Perth Scuba's Blue Destiny and Bucket List Diver) leave Fremantle in the morning and reach Thomson Bay in about 45-60 minutes; the Transit Reef wrecks are usually picked up on a mooring just outside the bay as a second, shallow dive. Private boats launch at Fremantle, Woodman Point or Hillarys and should use a public mooring rather than anchor inside the Kingston Sanctuary Zone.

It is also possible to catch the Rottnest Express or SeaLink ferry to the main jetty and kayak or make a long surface swim north from the Thomson Bay beach, but the route crosses a busy boat channel and a tow float and flag are essential.

Transit Reef is on the north-east corner of Rottnest and is protected from the prevailing south-west swell and sea breeze, which is why it is a fall-back site when the south and west coasts are blown out. It becomes uncomfortable and surgy in north-westerly winds and winter frontal weather, and divingwawrecks gives a working limit of under 2 m swell. Visibility is usually 5-15 m; sand movement in winter storms periodically covers and uncovers parts of the wreck.

Morning easterlies in summer give the flattest water. Boat traffic in the Thomson Bay approaches is heaviest on summer weekends and holidays.

Tie off on the public mooring, descend onto the reef beside the hull and start at the boiler. Swim the length of the upright hull (about 50 m), looking into the ribs and along the gunwales for coal and bottle fragments, then cross the sand and reef to the Denton Holme to the north-west. Return via the reef ledges and small caves, keeping to 4-6 m, and make your safety stop on the mooring line.

The Janet is about 80 m east if air allows.

Perth Scuba (Blue Destiny, Fremantle) and Bucket List Diver include the 'Three Wrecks' as a regular second dive on Rottnest day trips when swell allows; Dolphin Scuba runs it in winter. Glass-bottom and semi-submersible tour boats also visit.