Japanese technology company OKI has signed a supply contract with Mitsubishi Heavy Industries (MHI) to provide towed passive sonar and related equipment for the manufacturing of Australia’s new general-purpose frigates.
The contract covers equipment for the first three of the 11 frigates planned under the Australian Government’s General Purpose Frigate program, according to OKI.
Australia selected Japan’s FY2024 improved Mogami-class frigate, known as the 06FFM, for the program in August 2025. OKI said the vessel design includes its towed passive sonar and related equipment, with the company’s track record on Mogami-class frigates contributing to the selection.
The contract represents OKI’s first overseas transfer of defence equipment, the company said.
OKI has more than 90 years of experience in underwater acoustic technologies and has designed and manufactured underwater acoustic sensors and related equipment, primarily for defence applications.
It also supports sonar systems used by the Japan Maritime Self-Defense Force across their lifecycle, including design and maintenance.
Under the new contract with MHI, OKI will supply the sonar equipment for the Australian program using its existing technologies and expertise.
The company said the agreement forms part of its strategy under Management Plan 2031 to strengthen its defence and ocean-related businesses, which it identifies as priority areas under the Japanese government’s growth strategy.
OKI also said it plans to expand production capacity and strengthen overhaul capabilities in response to expected demand in the defence sector, while describing the Australian project as a contribution to maritime safety in Japan and internationally.
