UK and US F-35Bs Conduct First Joint Operations from Japanese Carrier JS Kaga

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For the first time, British and American F-35B Lightning II short take-off and vertical landing (STOVL) fighter jets have operated together from the Japanese helicopter carrier JS Kaga (DDH-184), marking a historic step in allied naval aviation. The UK Carrier Strike Group confirmed the milestone on 9 August 2025, releasing images of Royal Navy and US Marine Corps pilots conducting cross-deck landings during joint drills in the Western Pacific.

The F-35B Lightning II, developed by Lockheed Martin, is the STOVL variant of the fifth-generation stealth multirole fighter. Capable of strike missions, air defence, intelligence gathering and electronic warfare in contested environments, the aircraft combines stealth with supersonic performance and advanced sensor fusion. Its swivelling exhaust nozzle and lift fan system allow it to operate from short-deck ships without catapults or arrestor wires, enabling it to take off and land vertically. The Royal Navy currently deploys F-35Bs from HMS Queen Elizabeth and HMS Prince of Wales, while the US Marine Corps operates them from amphibious assault ships.

JS Kaga is the second Izumo-class vessel of the Japan Maritime Self-Defense Force, commissioned in 2017. Initially designed for anti-submarine warfare and search-and-rescue helicopter operations, the 248-metre, 27,000-tonne vessel is being converted into a light aircraft carrier to operate F-35Bs. This modernisation includes reinforcing the flight deck to withstand the heat and pressure of vertical landings, reshaping the bow for fixed-wing operations, upgrading aviation fuel and ordnance systems, and enhancing air traffic control and maintenance facilities.

Japan approved the purchase of 42 F-35Bs in 2019 under the US Foreign Military Sales programme, with the deal covering aircraft, mission systems, spares, training and maintenance support. The first deliveries are expected in the late 2020s, with operational deployment planned aboard both JS Kaga and her sister ship, JS Izumo, once conversions are complete.

The 9 August drills are more than symbolic. Hosting UK and US F-35Bs gives Japanese deck crews and aviation technicians valuable hands-on experience in managing advanced fighter operations at sea, from deck handling to maintenance routines. This knowledge will help Japan achieve operational readiness more quickly when its own F-35B fleet enters service.

Kaga’s transformation into a light aircraft carrier is part of Japan’s broader strategy to bolster deterrence in the Indo-Pacific. Regional security concerns, including China’s expanding naval capabilities and North Korea’s missile programme, have driven Tokyo’s decision to restore fixed-wing carrier aviation for the first time since the Second World War. The ability to deploy F-35Bs at sea will extend Japan’s reach, protect key sea lanes and strengthen integration with allied carrier strike groups.

The joint operations between Japan, the UK and the US underscore a deepening trilateral defence partnership. By proving that UK and US F-35Bs can operate from a Japanese carrier, the exercise enhances tactical flexibility and reinforces the capacity for rapid deployment, force projection and mutual support in contested waters. For all three nations, the milestone demonstrates a shared commitment to maintaining stability and a credible deterrent in a strategically vital region.