Following statements from Japan’s Minister of Defense, the delivery of the first six F-35B Lightning II fighters for the Japan Maritime Self-Defense Force (JMSDF) and its helicopter carriers, initially scheduled for March, has been delayed until at least April. The minister also mentioned that subsequent deliveries expected after 2025 should remain unaffected.
These F-35Bs are part of a 2019 purchase agreement for a total of 42 units, intended for use aboard JMSDF’s Izumo-class helicopter carriers. To accommodate the fifth-generation aircraft, modifications to the ships’ decks are necessary. The acquisition of the initial batch was expedited in October 2023, when it was announced that the first six units would be delivered by March 2024, a deadline that has not been met.
The delay primarily stems from setbacks on Lockheed Martin’s end. In July 2024, the Pentagon authorized the company to resume deliveries, which had been paused due to incomplete development of the F-35’s Technology Refresh 3 software update. Although deliveries have resumed, the update is not expected to be finalized until 2025, meaning delivered aircraft are currently limited to training operations. For Japan, this limitation is less critical as its F-35Bs are still in their initial service introduction phase.
By late May, other Indo-Pacific countries, such as Australia, South Korea, and Singapore, had already received successive batches of fifth-generation aircraft and placed orders for additional units.
Regarding the helicopter carriers, the JS Izumo (DDH-183) is currently undergoing its second phase of conversion at the Japan Marine United shipyard in Yokohama. This phase involves reshaping the flight deck into a rectangular configuration similar to U.S. Navy Wasp- and America-class amphibious assault ships.
The JS Kaga completed its first phase of conversion, which included bow modifications, in April 2024. The ship then sailed to the U.S. West Coast for F-35B compatibility trials. During its deployment, which concluded on November 20, the Kaga underwent further bow redesign, application of heat-resistant flight deck coatings to handle the F-35B’s engine thrust, and the installation of lighting for nighttime operations. A second conversion phase is scheduled for fiscal year 2026 and is expected to conclude by fiscal year 2028.
Japan is unlikely to achieve initial operational capability for F-35B operations from its carriers until 2029 or 2030. However, the timeline could be shortened if Japan qualifies its pilots and aircraft through training or operational deployments aboard a partner nation’s vessel or by embedding pilots within an operational F-35B squadron of a partner country while awaiting the completion of carrier conversions.
Lastly, the Ministry of Defense is reviewing the exact delivery timeline. It plans to establish a temporary F-35B squadron at Nyutabaru Air Base by the end of fiscal year 2024, which ends on March 31, to prepare for the aircraft’s arrival. The ministry initially planned to deploy the aircraft at the base by the end of fiscal year 2024, but the timeline has been pushed back to fiscal year 2025, according to Minister Nakatani.
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