This is the stern section of Japanese midget submarine Ha-21, which took part in the attack on Sydney in June 1942.
It used to be stored in the RAN heritage storage facility on Spectacle Island (which has since been closed). In 2023 it was put on display in a temporary exhibition at the ANZAC Memorial, in Hyde Park, Sydney, which is where the photograph was taken. In 2024 the display in Hyde Park was removed, and the stern section relocated to the Australian National Maritime Museum in another temporary display.
As for the rest of the submarine, the conning tower is on display in the RAN Heritage Centre on Garden Island, Sydney. The RAN Heritage Centre closed to the public in 2024, however as of June 2025 the centre’s artefacts were still housed within the building on Garden Island.
The bow section of Ha-21 is held by the Australian War Memorial in Canberra, where it is combined with the conning tower and stern section of sister-submarine Ha-14 to form a composite display.
