The US Defense Security Cooperation Agency (DSCA) has announced that the State Department has approved the acquisition of 105 Lockheed Martin F-35 Lightning IIs by Japan.

The July 9 announcement says Japan plans to acquire 63 more F-35A conventional take off and landing (CTOL) versions and 42 of the vertical take-off and landing (VTOL) variant. These numbers line up with a December 2018 announcement by Japan of its intention to acquire additional F-35s, including the F-35B for operations from its Izumo class helicopter destroyers.

The DSCA notice says the 105 F-35s will cost an estimated US$23.11bn ($A33.11bn), and will include five spare P&W F135 engines, and all of the usual US Government and contractor training, logistics, spares, ground support equipment, and delivery support.

Japan already has about 20 F-35As in service of a total of 42 aircraft on order, 40 of which will be built by Mitsubishi Heavy Industries at its final assembly and checkout (FACO) facility before Japan’s production switches to US-built aircraft.

The 27,000 tonne Izumo was recently reported as being part-way through its modification cycle to accommodate the F-35Bs, work which will include the installation of heavier deck plating, additional fuel bunkerage, communications, and landing and air traffic control systems.