As part of Operation Highmast and the deployment of Carrier Strike Group 25 (CSG25) in the Indo-Pacific region, a historic event occurred in the bilateral relationship between Japan and the United Kingdom: for the first time, British F-35B stealth fighters landed on the Japanese helicopter carrier JS Kaga (DDH-184) during joint naval maneuvers in the waters of the Philippine Sea. This operation, which also included the participation of U.S. Marine Corps (USMC) F-35B aircraft, represents a significant advance in the capabilities of the Japan Maritime Self-Defense Force.
The landing took place in the Philippine Sea, where the aircraft carrier HMS Prince of Wales and the JS Kaga conducted cross-deck operations with British and American F-35B fighters. Although U.S. Marine Corps aircraft had already operated from the Kaga during previous tests, this was the first time a British F-35B performed this maneuver, highlighting the level of coordination achieved between the two navies.
The maneuvers are part of a series of combined air-naval exercises including the participation of the USMC’s VMFA-242 “Bats” squadron. During this phase of the deployment, the STOVL (short takeoff and vertical landing) fighters of the Royal Air Force — No. 617 Squadron “Dambusters” — and the Royal Navy — Naval Air Squadron 809 — demonstrated their ability to operate in coordination from naval platforms of different allied countries.
This exercise’s cooperation has recent precedents. In November 2023, officers from the Japan Maritime Self-Defense Force (JMSDF) visited the HMS Prince of Wales to study firsthand F-35B operations. Subsequently, in August 2024, a Japanese delegation inspected the Italian aircraft carrier ITS Cavour during its stop at Yokosuka Naval Base, deepening trilateral cooperation between Italy, the United Kingdom, and Japan — countries that will operate both the F-35A and F-35B variants, as well as collaborate on the GCAP program.
Japan, which decided in 2018 to acquire 42 F-35Bs, recently received its first units. The incorporation of these fighters aims to provide power projection capability to the Izumo-class helicopter carriers, currently undergoing conversion works to operate vertical takeoff and landing aircraft. The JS Izumo is expected to begin operations with the F-35B in 2027, followed by the JS Kaga in 2028, which will operate as light aircraft carriers.
Modifications to both ships include a new angular design of the flight deck, reinforcements, and systems adapted to mitigate the heat generated by the F-35B engines. In previous tests, Japan had already allowed operations with foreign F-35Bs on the Izumo in 2021 and more recently on the Kaga, always with non-Japanese pilots.
*Cover image credits: United Kingdom Royal Navy Carrier Strike Group
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