Meet the site
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. J4 launched at Portsmouth on 2 February 1916, commissioned on 17 July 1916 and transferred to the RAN on 25 March 1919. After sale to the Melbourne Salvage Company in January 1924 she sank by accident alongside at Williamstown on 10 July 1924, was refloated on 6 December 1926 and finally scuttled four miles outside the Heads on 28 April 1927 – the last of the four to go. The Melbourne Bottom Scratchers relocated her and fixed a bronze plaque to the conning tower, rediscovered on 16 May 1982. The '26 m sub' lies on its keel running north–south with the bow pointing seaward. The bow section broke off during scuttling, so the four torpedo tubes and the modified bow structure are laid open and can be examined without any penetration. The conning tower is intact and in excellent condition, the best of any of the boats, and is usually wrapped in a cloud of fish that makes it the classic photograph. Aft, the casing is open in places and the hull slowly merges into the limestone reef at the stern. Inside, the bulkheads that once held the boat together at depth and the engine bed are visible through the hatch openings. Full-length penetration is possible through multiple hatches, but the wreck is exposed to surge and the Scuba Doctor's warning is blunt: unwary divers can be sucked in and catapulted through the interior. That same surge keeps the interior remarkably free of silt and the exterior scoured and colourful – on a clear day with 20 m visibility the whole 84 m hull can be taken in from mid-water, and it rates as one of Melbourne's top dives. At 19–28 m it is within Advanced Open Water limits with generous bottom time, which is why it is the most dived wreck outside Port Phillip and the usual first Graveyard dive for anyone progressing from the bay sites.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
J4 Submarine is recorded as Wreck in Port Phillip Heads. The listed access is boat (day trip). Confirm the actual meeting point, route and permission to visit; a map pin does not establish any of these.
Topics flagged by the stored research
These are questions prompted by the existing notes, not a verified or complete hazard assessment.
- Other water users
- Ask about vessel activity, exclusion areas and the agreed surface arrangements.
- Lines and obstructions
- Discuss any known entanglement concerns and the suitability of the planned area.
- Planned depth
- Confirm the intended route and training requirements; the recorded maximum is not a target.
- Water movement
- Ask how swell and local exposure affect the proposed entry, exit and route.
- Overhead environments
- Ask whether the plan stays entirely in open water. A wreck or cave listing is not permission or training to enter.
Historical access notes exist for this record, but have not been independently verified for current use. Request current directions from the operator or site manager rather than following an old entry description.
Questions, answered
Is J4 Submarine suitable for my certification?
The record lists Advanced Open Water. That does not establish suitability for every route or day. Share your training, recent experience and equipment needs with the operator and ask about the specific proposed dive.
Can I book J4 Submarine through YouDive?
YouDive is an independent research directory. Contact an operator directly to confirm whether it currently runs the trip, the inclusions and the booking terms.
What you might see
Bullseyes, butterfly perch, magpie perch, leatherjackets, old wives, yellow zoanthids, sponges, southern rock lobster, blue devilfish, Australian fur seals at the surface
Location
Eastern Ships' Graveyard about 3 km south-west of Point Lonsdale, the shallowest and most dived of the offshore J-boats.
Facilities nearby
Departure from Queenscliff Harbour (parking, toilets, cafes, fills at Dive Victoria/Queenscliff Dive Centre) or Portsea Pier (parking on Point Nepean Road, toilets, cafes).
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
scubadoctor.com.auscubadoctor.com.auscubadoctor.com.auen.wikipedia.orgRecord updated 26 Sept 2026. Source claims are being reviewed.
