

The HMAS J2 is a decommissioned Royal Australian Navy submarine sitting upright on the seafloor off Victoria at 37 to 39 metres, making this firmly deep diving territory. The wreck is largely intact, and the combination of confined spaces, potential low visibility down to 1 metre, cold water, and overhead environments demands solid buoyancy control and prior wreck experience. Visibility can reach 10 metres on a good day, but plan for less. Wobbegong sharks rest against the hull, blue devilfish tuck into crevices, and crayfish shelter beneath overhangs. Schools of fish work the water column above, while benthic invertebrates colonise most exposed surfaces. Mild current is typical, though conditions can strengthen.
-38.31358, 144.58007
Summer through autumn (December to May) offers the most reliable conditions for this site. Given the depth and the potential for low visibility, arrive with a primary and backup torch and confirm your bottom time calculations before descending.
The wreck is located 3 kilometres South of Point Lonsdale and is accessed by dive charter boats from Portsea or Queenscliff.
The HMAS J2 is considered the most hazardous of the J-class submarine wrecks. The hull is broken in two places, and the section behind the conning tower has collapsed. Penetration is not recommended due to the risk of fine silting, which can cause disorientation. The site is also in a shipping lane.
Depth
37-39m
Visibility
1-10m
Skill Level
Advanced
Entry
Boat
Boat required
Water Temp
10-20°C
Current
Mild
Typical Dive
55 min
Best Time
Jan, Feb, Mar, Apr, May, Dec
The HMAS J2 Submarine wreck sits at depths between 37 and 39 metres on the seabed off Victoria, Australia. This depth classification places it firmly in the deep diving category, requiring advanced certification and appropriate training. The wreck rests upright on the sandy bottom, making depth management critical throughout the dive.
Diving the HMAS J2 Submarine requires advanced open water certification, deep diving specialty, and wreck diving specialty qualifications. The wreck's depth of 37 to 39 metres, combined with overhead environment hazards and low visibility conditions, makes these certifications essential for safe exploration. All dives on this Melbourne-area wreck are conducted with experienced operators who verify credentials before departure.
The best months to dive the HMAS J2 Submarine are December through May, corresponding to the Australian summer and early autumn. During this period, water temperatures reach 15 to 20 degrees Celsius and sea conditions are generally calmer. Visibility ranges from 1 to 10 metres throughout the year, with better conditions typically occurring during the recommended months.
The HMAS J2 Submarine wreck hosts wobbegong sharks, blue devilfish, southern rock lobster (crayfish), and schools of fish around the structure. Benthic invertebrates have colonised the submarine's exterior surfaces, creating a thriving artificial reef ecosystem. The wreck's position off Melbourne attracts diverse Victorian temperate species seeking shelter and feeding opportunities.
The HMAS J2 Submarine is strictly an advanced dive site and completely unsuitable for beginner divers. The 37 to 39 metre depth, overhead environment penetration risks, variable visibility of 1 to 10 metres, and cold water temperatures of 10 to 20 degrees Celsius demand extensive experience. Only divers holding advanced, deep, and wreck specialties should attempt this challenging Melbourne wreck dive.
Access to the HMAS J2 Submarine is exclusively by boat from Melbourne, Victoria, with no shore entry possible. Charter operators specialising in wreck diving run scheduled trips to the submarine during favourable conditions. There are no facilities at the site, and all equipment, including thermal protection for 10 to 20 degree Celsius water, must be brought aboard.
The HMAS J2 Submarine presents multiple hazards including the overhead environment inside the wreck, cold water temperatures of 10 to 20 degrees Celsius, and low visibility ranging from 1 to 10 metres. Entanglement risks from fishing lines and debris, boat traffic above, and the deep depth of 37 to 39 metres require constant vigilance. Mild to strong currents can also affect the dive, demanding excellent buoyancy control and navigation skills.
A 7mm wetsuit or semi-dry is recommended for diving at HMAS J2 Submarine in Melbourne. Water temperatures range from 10°C to 20°C.
HMAS J2 Submarine in Melbourne has depths ranging from 37 metres to 39 metres.
A typical dive at HMAS J2 Submarine in Melbourne lasts approximately 55 minutes. Actual dive time depends on depth, air consumption, and conditions.