MHI launches JS Yoshii, the final Mogami-class frigate for Japan

On 22 November, Mitsubishi Heavy Industries (MHI) launched the future JS Yoshii (12), the final stealth frigate in the new Mogami class being introduced by the Japan Maritime Self-Defense Force (JMSDF). The ceremony was held at the company’s Nagasaki facilities, where the entire series of 12 new vessels intended to modernise Japan’s surface fleet has been developed, designed and built.

JS Yoshii completes the Mogami-class frigate series

The Mogami class is currently among the most modern frigates operated by the Japan Maritime Self-Defense Force. Featuring a stealth design, these vessels displace around 3,900 tonnes, measure 133 metres in length and can reach a maximum speed of approximately 30 knots. The ships form part of a Japanese Ministry of Defence order for 12 units awarded to Mitsubishi Heavy Industries, which has built them through its associated shipyards in Nagasaki and Tamano.

Before the JS Yoshii launch ceremony, JS Tatsuta-the eleventh frigate in the series-was launched in July and has continued to follow its construction timetable without incident. Since then, it has progressed through its build phase and undergone a range of trials ahead of delivery and entry into service with the Japan Maritime Self-Defense Force by the end of fiscal year 2026, which concludes on 31 March 2027.

Regarding the preceding frigates, MHI is currently completing final trials and outfitting work on JS Natori and JS Nagara, the ninth and tenth vessels in the class. Their deliveries are scheduled for the end of this year and the beginning of next year, respectively.

The next stage for JS Yoshii will involve final equipment integration, focused on its upperworks, before it proceeds with the required sea trials ahead of delivery and commissioning, likewise planned for the end of fiscal year 2026. To date, eight ships have already entered service and been assigned to Escort Divisions: JS Mogami, JS Kumano, JS Noshiro, JS Mikuma, JS Yahagi, JS Agano, JS Niyodo and JS Yubetsu.

Mogami “FFM”: the next evolution of the Mogami class

Although the Mogami class represents one of Japan’s most advanced naval developments, an evolved version of the design is already in development under the provisional designation of the Mogami-class “improved FFM frigates”. According to information released so far, these vessels will offer greater displacement, larger dimensions and enhanced combat capability, as well as substantial improvements in anti-submarine warfare, surface warfare and multi-role operations compared with the original Mogami class.

In March, Japan’s Ministry of Defence Acquisition, Technology & Logistics Agency (ATLA) awarded Mitsubishi Heavy Industries (MHI) two contracts in 2024 worth US$ 1.200 billion to begin construction. The platforms are expected to have an estimated service life of 40 years, while the programme is projected to involve investment of US$19.200 billion, with the first improved vessel due for delivery in 2028.

According to the Japanese Ministry of Defence, the new FFM class will displace 4.880 tonnes and feature a hull 142 metres long with a beam of 17 metres, narrower than the 17.4 metres of the original Mogami class. However, several features will be retained, notably a 32-cell MK41 vertical launch system (VLS), the SeaRAM close-in defence system, and the ability to fire eight anti-ship missiles from two quadruple launchers positioned amidships. The ships will also carry a 127mm main gun and an active electronically scanned array radar integrated into the main mast.

Australia chooses the improved FFM Mogami frigate

While Japanese shipyards continued their construction work, significant news concerning the class’s future emerged in August. In a milestone for Japan’s naval industry, the Australian government confirmed its selection of the improved Mogami variant as the replacement for the Anzac-class frigates that have served with the Royal Australian Navy for decades.

This is a notable achievement, as Mitsubishi Heavy Industries’ Japanese stealth frigate was selected over the German proposal based on Thyssenkrupp Marine Systems’ MEKO A-200 class to equip the Australian Navy with 11 new general-purpose frigates.

While further details have not been provided, contracts confirming Australia’s decision are expected to be signed in 2026. The first three ships are expected to be built in Japan and the remaining eight in Australia, with the first frigate scheduled for delivery in 2029 and entry into service in 2030.