The Denton Holme lies almost alongside the Macedon and is the larger of the Transit Reef iron wrecks. She was a 65 m iron barque of 988 tons (998 tons in some sources) and was wrecked on 25 September 1890 carrying cement, iron piping and about 300 tons of general merchandise; some accounts also mention whisky. She struck the same reef that had claimed the Macedon seven years earlier, broke her back and was written off as not worth refloating.

Unlike the upright Macedon, the Denton Holme's hull has collapsed and spread over a large area of reef, so the site is more of a wreck trail than a single ship. The exception is the bow, which still stands up from the reef to within a metre of the surface at low tide and is the landmark most divers remember. Around it are hull plates, frames, lengths of pipe, lumps of set cement cargo, coal and glass. Immediately north of the wreck the limestone reef opens into an impressive cave and overhang system at 5-7 m, which is the other reason to linger here: bullseyes and sweep fill the caves, and western rock lobster sit under the ledges.

The Denton Holme is almost always dived together with the Macedon on one tank, and the Janet and Gem are within a short swim. The combination of shallow depth, shelter from the south-west and easy navigation makes this Rottnest's most reliable beginner wreck site and a good snorkel when the water is flat. It is inside the Kingston Sanctuary Zone and is a protected historic shipwreck.

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.

Sheltered from south and south-west swell by the island itself, so usually diveable when the southern and western sites are not. Surge increases sharply in north-westerly winds and winter storms; divingwawrecks recommends under 2 m of swell. The bow is close to the surface at low tide, so large swell breaks over it.

Visibility 5-15 m, best on calm summer mornings and between winter fronts; sand shifts after storms. Heavy weekend boat traffic in summer.

Combine with the Macedon: descend at the mooring, explore the Macedon first, then fin north-west to the Denton Holme's scattered hull. Follow the broken plates to the standing bow, then drop into the cave system on the reef north of the wreck at 5-7 m. Return along the reef edge to the mooring for a safety stop; keep well clear of the bow in any swell.

Dived with the Macedon on the 'Three Wrecks' mooring by Perth Scuba and Bucket List Diver on Rottnest day trips (weather permitting) and by Dolphin Scuba in winter; also a staple of Perth dive clubs with private boats.