Training for the 2026 Escort Ship Kaga with F-35B, a Test Case Before the 42 Aircraft System

The brief notification that "Kaga" is entering Iwakuni Base was understated compared to the significance of the ship's name. According to a report by USNI News on May 20, the Japan Maritime Self-Defense Force's escort ship "Kaga" (DDH-184) is scheduled to visit the U.S. Marine Corps Air Station Iwakuni from June 1 to 4, carrying the necessary equipment for F-35B landing and takeoff training. The training itself is expected to take place in June, including cross-deck operations, but details such as the operational area are still being adjusted.

Preparation Stage Indicated by Iwakuni Port Call

"Kaga" is the second ship of the Izumo-class escort vessels, featuring a flight deck approximately 248 meters long. However, having a long deck does not equate to being usable as a fleet air combat force. The key point this time is to verify each aspect of landing and takeoff, deck control, supply, maintenance equipment, and communication procedures using the U.S. Marine Corps' F-35B. The F-35B on the Japanese side is owned by the Air Self-Defense Force, while the ship is operated by the Maritime Self-Defense Force. Connecting the cultures of these two organizations will take more time than mere vessel modifications.

42 F-35Bs and Two Decks

Japan plans to ultimately acquire 42 F-35Bs, with the initial aircraft entering the training phase at Nittahara Base with support from the U.S. Marine Corps. According to USNI News, the first three aircraft were delivered last year, and an additional three were delivered this year. "Izumo" is currently undergoing modifications for the second phase, expected to be completed by March 2028, and "Kaga" is also anticipated to enter its final modifications, expected to be completed by March 2029. In other words, the training in June 2026 is not the final form but a practical test before reaching a two-ship system.

Significance in the First Island Chain

"Kaga" is set to participate in the Indo-Pacific Deployment 2026 alongside "Fuyuzuki" and "Mashu" as part of the 2nd Surface Unit, and is also expected to head to RIMPAC 2026, which will take place around Hawaii from June 24 to July 31. This indicates that the JMSDF is not limiting F-35B operations to a symbolic capability domestically but is attempting to connect with the U.S. Navy and Marine Corps' expeditionary operational system. In the defense of the Nansei Islands, what is needed is not just missiles to strike enemy ships. A deck that can rotate patrol, air superiority, anti-ship strikes, casualty evacuation, and resupply at the same operational tempo is required.

Cautious View on Aircraft Carrier Conversion

However, the author is somewhat cautious about the term "light aircraft carrier conversion." There is a significant distance between peacetime landing and takeoff training and continuous air operations in times of crisis. While the F-35B is capable of short takeoff and vertical landing, without sufficient ammunition load, fuel, maintenance personnel, spare parts, and recovery capability in case of deck damage, deterrence will end up being a thin facade.

The question posed in this training is not whether the F-35B can land on "Kaga." It is about how quickly Japan and the U.S. can prepare for the next sortie after landing.

It is also noteworthy that the Iwakuni City Council expressed concerns about resident anxiety and the routine nature of port calls. Deterrence in the First Island Chain is influenced not only by the number of missiles and aircraft but also by friction management with the accepting municipalities. The most vulnerable aspect of Japan's aircraft carrier conversion may not be the heat treatment of the deck but the formation of political consensus when transitioning from peacetime to crisis.

Main Information Sources

• USNI News, May 20, 2026
• Japan Ministry of Defense notice cited by USNI News
• Iwakuni City Council document cited by USNI News