U.S. Navy sailors from USS Tripoli and U.S. Marine Corps (USMC) F-35B Lightning II aircraft belonging to VMFA-242 conducted flight operations aboard the Japan Maritime Self-Defense Force (JMSDF) ship JS Kaga as part of the ANNUALEX exercise. The activity adds to a series of bilateral cooperations focused on the operational integration of fifth-generation fighters with Japanese platforms.
JS Kaga is undergoing modernization to operate F-35B aircraft, as part of Japan’s program to modify both this ship and its sister ship, JS Izumo. The JMSDF aims to enable operations for the future fleet of 42 F-35Bs acquired by the country, although these aircraft will fall under the control of the Japan Air Self-Defense Force. In total, Japan plans to field 147 F-35s across the A and B variants.
In December 2024, JS Kaga returned to its base in Kure after completing a three-month deployment near the United States intended to evaluate its ability to operate F-35Bs. During that period, tests were conducted together with Air Test and Evaluation Squadron (VX-23) and personnel from the F-35 Patuxent River Integrated Test Force (Pax ITF), an organization with extensive experience in certifying the fighter’s naval variants.
Likewise, in August 2025 the ship marked a milestone in international cooperation. Within the framework of Operation Highmast and the Carrier Strike Group 25 deployment, United Kingdom F-35Bs landed for the first time on JS Kaga during joint maneuvers in the Philippine Sea. USMC F-35Bs also participated. The operation included cross-deck activities between HMS Prince of Wales and JS Kaga, strengthening interoperability among the naval forces of Japan, the United Kingdom, and the United States.
The recent ANNUALEX operations continue this trilateral cooperation and further consolidate the process of integrating F-35Bs with JMSDF vessels. VMFA-242 “Bats,” which has taken part in previous combined exercises, once again operated from Kaga, reinforcing the joint capability to employ STOVL aircraft on allied platforms.
Images obtained from the U.S. Pacific Fleet.
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