Asia Defense

Japan Approves Plans to Convert Izumo-Class Into F-35-Carrying Aircraft Carriers

Japan’s two largest warships will be converted into aircraft carriers over the next five years.

Franz-Stefan Gady
Japan Approves Plans to Convert Izumo-Class Into F-35-Carrying Aircraft Carriers

On the deck of the JS Izumo at port in Yokosuka, Japan.

Credit: Catherine Putz

The cabinet of Japanese Prime Minister Shinzo Abe officially approved on December 18 plans to convert the Japan Maritime Self-Defense Force’s (JMSDF) two largest warships — the helicopter destroyers JS Izumo, lead ship of the Izumo-class, and its sister ship the JS Kaga — into aircraft carriers capable of launching the F-35B, the U.S. Marine Corps variant of F-35 Joint Strike Fighter capable of vertical or short takeoffs and vertical landings (STOVL) without requiring a catapult launcher.

Japan’s new National Defense Program Guidelines (NDPG), which lay out the Japan Self Defense Force (JSDF) capability targets and needs for the next decade, call for the first deployment of Japanese aircraft carriers since the end of the Second World War. According to the fiscal 2019-2023 midterm defense buildup program, the conversion of the two 27,000-ton  helicopter destroyers is expected to take place over the next five years.

During the same time period, Japan is also slated to receive its first batch of 18 F-35B fighter jets capable of short takeoffs and vertical landings. Japan is set to procure 63 extra F-35As — the aircraft’s conventional takeoff and landing variant –and 42 F-35Bs, the U.S. Marine Corps’ short take-off and vertical landing (STOVL) variant of the aircraft, in addition to 42 F-35As already on order over the next decade. Japan currently has a total of 10 F-35As operational deployed.

Notably, the NDPG re-designates the Izumo-class as multi-purpose escort destroyers to comply with Japan’s pacifist constitution that limits JSDF capabilities to self-defense. “The planned modification to the Izumo-class carriers is to increase their applications,” Japan’s Minister of Defense, Takeshi Iwaya, said last week, downplaying the carrier’s offensive capabilities once retrofitted.

As I reported in May, a study released by the Izumo-class builder, Marine United Corporation (MUC), earlier this year concluded that the warships can be converted into full-fledged aircraft carriers with some modifications. Indeed, as I pointed out elsewhere, while large sections of the study remain classified, the Izumo carrier class has reportedly been designed to operate STOVL fighter jets right from the inception of the program and requires only minor modifications to accommodate the F-35B.

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Following modifications, the carriers would each only be capable of accommodating around a dozen F-35Bs.

Both the JS Izumo and JS Kaga have been principally designed for anti-submarine warfare since entering service over the past three years. “Its usefulness as an [anti-submarine warfare] ASW platform would be substantially reduced following the ship’s conversion as it would no longer be capable of carrying its full contingent of Mitsubishi-built SH-60k ASW helicopters and other ASW-related equipment,” I wrote last week.