According to official information from Japan’s Ministry of Defense, the Air Self-Defense Force will receive its first F-35B Lightning II stealth fighters in the coming days, following several months of delivery delays by the United States. The aircraft will be used to bolster the air defense capabilities of Japan’s islands, especially in light of the regional context marked by increased Chinese military activity.
In 2019, Japan confirmed the purchase of 42 F-35Bs—the short takeoff and vertical landing (STOVL) variant—with the aim of operating them from its two Izumo-class helicopter carriers, which are currently undergoing conversion to serve as light aircraft carriers. It is worth noting that in the final months of 2024, the JS Kaga (DDH-184) was sent to the United States to evaluate its capabilities for operating stealth fighters. A second phase of the ship’s conversion is scheduled for fiscal year 2026 and is expected to be completed by fiscal year 2028.
However, the introduction of the F-35Bs was not without setbacks. The primary issue was the delay in the development of the Technology Refresh 3 (TR-3) software update package, which led to a temporary halt in deliveries by Lockheed Martin. Although the jets destined for Japan had already completed production and flight testing, their originally scheduled delivery in March 2025 was postponed again.
Recently, following the accumulation of these delays, Japan’s Ministry of Defense confirmed that the first four F-35Bs will be delivered in the coming days, with operational deployment beginning on August 7 at Nyutabaru Air Base. It also stated that eight units are expected during fiscal year 2025, while the delivery date for the remaining four has yet to be finalized.
Despite the announcement, the repeated delays have had broader impacts on the planned timelines. The most significant of these is the timeline for the aircraft to reach Initial Operational Capability (IOC) for carrier-based operations, which is now projected for 2029 or 2030. Nevertheless, several initiatives are being explored—leveraging Japan’s cooperation framework with countries such as the United States—to shorten this projection.
Finally, it is worth mentioning that, in light of these delays and to ensure immediate operability with the F-35B, Japan established a temporary squadron at Nyutabaru Air Base in March 2025, aiming to maintain operations through 2029–2030. The plan involves deploying up to 30 fighters at Nyutabaru, due to construction delays at the new facility on Mageshima Island. By the end of the decade, Japan is expected to complete the deployment of its full fleet of 42 F-35Bs, including the eight aircraft scheduled to be in service by 2025.
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