Courier was a steel screw steamer built by C. S. Swan and Hunter at Newcastle-on-Tyne in 1887, 67.3 m long and about 660 tons displacement, brought out for the Melbourne–Geelong passenger trade, on which she began work in January 1888.

In the late 1880s she was fitted out as an armed auxiliary of the Victorian Navy, and she spent decades as a bay steamer and excursion boat before being sold for scrap. On 29 March 1928 (some sources say 1929) the tug Otter towed her three miles outside The Heads and she was sunk in the Graveyard. The wreck lies in 37–42 m in the pilot boarding ground.

The hull has mostly collapsed, but the bow and stern sections survive, both lying over to starboard. The foredeck is the best part: it still retains a considerable amount of its timber planking, stands about 7 m off the bottom and is a rare thing in Bass Strait, where most wooden decking has long gone. Aft of it two boilers sit in line on what was the main deck, and beneath them large crayfish shelter.

The stern is less structurally intact but still readable, with the rudder area identifiable. Courier is one of the most colourful wrecks in the Graveyard. Because it sits where tidal flow through The Rip fans out, every surface carries brightly coloured multi-form sponges, anemones, hydroids, ascidians and soft corals, with bright yellow zoanthids over the bow.

Butterfly perch, bullseyes and old wives school over the structure and blue devilfish are seen occasionally. At 40 m the dive is short and every visit is a decompression dive, and its position in the pilot boarding ground means charters need a clear window with no pilot transfers. It suits technical-trained or very experienced deep divers who want colour and history rather than penetration, and it is often paired with J2 on a deep day.

Boat only. Charters leave from Queenscliff Harbour (Red Boats, Dive Victoria Group) or Portsea Pier (Dive Victoria Group, Bayplay); drive Melbourne–Queenscliff via the Geelong Ring Road and Bellarine Highway (about 1 h 40 min) or Melbourne–Portsea down the Mornington Peninsula Freeway (about 1 h 45 min). Private boats launch at Queenscliff (Larkin Parade) or Sorrento ramps; the wreck lies a few kilometres outside The Rip, so time the run through the Heads for slack or a following tide.

Boat time from Queenscliff is roughly 20–30 minutes and from Portsea 30–40 minutes in a fast RIB, longer in a displacement charter boat. Gear is loaded at the harbour; there is parking at Queenscliff Harbour and along Point Nepean Road at Portsea.

Fully exposed Bass Strait. South-westerly swell is the killer: most charters will not run on a forecast over about 1.5 m, and anything from the south or west over 2 m makes the site undiveable and the passage through The Rip dangerous. Northerly and north-easterly winds flatten the sea; a calm morning after several settled days gives the best visibility (often 15–25 m in autumn and winter).

Surge is felt on the wreck in any swell over 1 m. Tidal streams outside The Heads are weaker than inside but still run; charters aim for slack water at Port Phillip Heads or a favourable tide for the transit. Winter westerlies close the site for weeks at a time.

The wreck sits in or near the shipping approach and pilot boarding ground, so a shot line, surface cover and a delayed SMB are mandatory.

Descend the shot to the foredeck (about 35 m at the top of the bow, rising 7 m off the bottom). Explore the planked foredeck and bow lying over to starboard, then move aft over the two in-line boilers on the main deck, checking beneath them for crayfish, to the less intact stern at 42 m. Return to the shot at 18 minutes; 15–20 minutes of decompression is normal.

Technical (decompression) dive. Normoxic trimix (e.g. 21/35) or EAN28 for the shallower end; plan on 15–25 min bottom time with 10–20 min of decompression on EAN50. Drop a weighted shot on the wreck, use a delayed SMB from the wreck or a decompression trapeze under the boat; the site is in a shipping approach so free-drifting deco is discouraged.

Dive Victoria Group and Red Boats (Queenscliff) include the Courier on deep/technical charters a few times a season when the pilot boarding ground is quiet; Bayplay occasionally. Not a weekly site.