Meet the site
On the night of 31 May 1942 three Japanese Type A midget submarines, launched from mother submarines off the Heads, entered Sydney Harbour. Two were destroyed or scuttled inside the harbour and were raised; the third, M24, commanded by Sub-Lieutenant Katsuhisa Ban with Petty Officer Mamoru Ashibe, fired both torpedoes from mid-harbour at about 12.30 am on 1 June. One passed under the Dutch submarine K-IX and struck the converted ferry HMAS Kuttabul, moored at Garden Island as a depot ship, killing 21 sailors. M24 then slipped back out through the Heads and vanished; for 64 years her fate was one of Australia's enduring naval mysteries. In November 2006 a group of recreational divers from the No Frills Divers club, working the deep grounds off the Northern Beaches, found her upright on sand in 55 m about 5 km off Bungan Head, Newport, just under half-buried. The discovery was announced on 1 December 2006 and a 500 m no-entry Protected Zone was declared the same day under the Historic Shipwrecks Act 1976; the site was added to the NSW State Heritage Register in December 2007 and penalties for disturbance run to A$1.1 million. The hull is generally intact but damaged by decades of trawling: the conning-tower plating has been torn off and external fittings ripped away. The remains of the two crew are presumed inside, and the site is treated as a war grave, with Japanese family members having visited to lay wreaths. It appears in this file because it is the most historically significant wreck on the Northern Beaches coast and because divers should know that it cannot be dived: access is by heritage permit for research and site management only, notwithstanding a 2012 announcement of occasional controlled recreational dives by ballot. Technical divers working the Trio, Birchgrove Park and Myola should keep well clear of the zone, which is marked on charts.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
M24 Japanese midget submarine (protected zone – no diving) is recorded as Wreck in Sydney Northern Beaches. The listed access is boat. 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.
- Planned depth
- Confirm the intended route and training requirements; the recorded maximum is not a target.
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 M24 Japanese midget submarine (protected zone – no diving) suitable for my certification?
The record lists Technical (decompression). 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 M24 Japanese midget submarine (protected zone – no diving) 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
Not documented; sand-plain species (kingfish, jewfish, rays) expected on comparable wrecks
Location
The Type A midget submarine M24 that torpedoed HMAS Kuttabul in the 31 May–1 June 1942 attack on Sydney Harbour, found in November 2006 about 5 km off Bungan Head, Newport, upright and half-buried in sand at 55 m; a 500 m radius no-entry Protected Zone under the Historic Shipwrecks Act – recreational diving is prohibited.
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
en.wikipedia.orgRecord updated 26 Sept 2026. Source claims are being reviewed.