The J-class were the fastest submarines in the world when they were laid down for the Royal Navy in 1915: 84 m long, 1,210 t surfaced and 1,820 t submerged, driven by three diesels for 19 knots on the surface. Six survivors of the class were gifted to the Royal Australian Navy in March 1919, sailed out with the depot ship HMAS Platypus, arrived in Sydney on 15 July 1919 and were based at Geelong from 1920. Post-war budget cuts saw them paid off at Western Port on 12 July 1922, and in January 1924 the Melbourne Salvage Company bought the flotilla for scrap.

J5 was launched on 9 September 1915 and commissioned on 6 May 1916 with the 11th Flotilla. Stripped at Williamstown, she was towed out and scuttled off Barwon Heads on Friday 4 June 1926, taking two hours to disappear; the Geelong Skindivers Club relocated her on 4 May 1974. The 'Yellow Submarine' sits upright on a sandy bottom, bow to the south, and gets its name from the sheet of yellow zoanthid anemones that covers the bow, stern and conning tower so thickly that the steel is barely visible.

The conning tower stands proud of the deck at about 30 m and is the busiest part of the wreck for fish: bullseyes, longfin pike, barber perch and splendid perch school here in numbers. Forward, the narrow, sleek bow is gradually collapsing but the four torpedo tubes are still clear; aft, the rudder, propeller-shaft supports and stabiliser frames are all recognisable. Although the boat was stripped before sinking, there is a surprising amount to see inside.

Large deck openings along the length let light in and allow penetration at several points, from the torpedo room forward to the crew spaces in the stern. The bow interior silts easily and demands good buoyancy and a line; the midships openings are more forgiving. It is excellent for photography inside and out.

At 25–36 m J5 is a step beyond J4 and is usually dived as the deep dive of the day on nitrox. It is intact, colourful and relatively sheltered from the worst shipping traffic, which makes it the favourite of the four for many regular Graveyard divers and a regular fixture on Dive Victoria and Red Boats charter calendars.

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 conning tower at about 30 m. Head south along the casing to the bow, where the four torpedo tubes sit at 36 m on the sand, then return along the other side of the deck past the large deck openings to the stern to see rudder, propeller shaft supports and stabiliser frames. Trained divers can drop through the deck openings amidships where light penetrates.

Turn at 20–22 minutes and ascend the shot; expect a short deco or extended safety stop.

Within recreational limits on air or EAN28–32 but an SMB, redundant gas (pony or twinset) and a computed deco plan are expected; many divers run it as a light-deco dive on nitrox with a 50% stage. Shot line descents and ascents only – free ascents in the shipping approach are not acceptable.

Dive Victoria Group (Portsea and Queenscliff) – scheduled double-dive charters most weekends in season, weather permitting; Red Boats (Queenscliff) – regular weekend and weekday charters; Bay City Charters (Portsea/Queenscliff) and Chimney Rock Charters (Queenscliff) – regular weekend charters; Bayplay (Portsea) – occasional advanced charters. All treat the site as a deep/advanced dive and run it on the calmest days of the week. Second only to J4 in charter frequency; often paired with J4 or the Coogee on a double-dive day.