On May 18, 2026, the Yomiuri Shimbun, one of Japan’s leading national newspapers, reported that the Japan Self-Defense Forces (JSDF) are considering equipping unmanned aerial vehicles (UAVs) with airborne early warning (AEW) radar systems.
According to the report, this move is linked to the Japanese government’s plan to incorporate enhanced surveillance and monitoring capabilities on the Pacific side of Japan into the revised “Three Security-Related Documents,” which are scheduled to be updated later this year.
In particular, the Japanese government has grown increasingly concerned about Chinese military bombers operating through the Bashi Channel — the strait between Taiwan and the Philippines — and advancing into the Pacific Ocean since 2017. Furthermore, in 2025, two Chinese aircraft carriers conducted extended deployments in the Western Pacific, highlighting the need for closer monitoring not only of Chinese naval vessels but also of carrier-based fighter aircraft operations.
As a result, Japan’s Ministry of Defense and the JSDF are now rapidly strengthening their defense posture along the Pacific side of the country, an area that had previously been regarded as a “defense gap.”
The report specifically mentioned the MQ-9B SeaGuardian, which the Japan Maritime Self-Defense Force (JMSDF) plans to operate, as the UAV candidate for carrying the AEW radar system. Developed by the U.S. company General Atomics Aeronautical Systems Inc. (GA-ASI), the MQ-9B is an unmanned maritime patrol aircraft equipped with electro-optical sensors, signals intelligence collection antennas, and maritime surveillance radar systems, enabling it to continuously gather a wide range of intelligence while remaining airborne for more than 24 hours.
The JMSDF selected the MQ-9B at the end of 2024 as a platform intended to complement and partially replace missions currently performed by the manned Kawasaki P-1 maritime patrol aircraft. The aircraft will be based at Kanoya Air Base in Kagoshima Prefecture and Hachinohe Air Base in Aomori Prefecture. Initially, in FY2027, two MQ-9Bs will be operated at Kanoya by a civilian contractor to establish operational procedures for surveillance and monitoring missions. Subsequently, two additional MQ-9Bs will be deployed from FY2028 onward, bringing the total to four aircraft operated directly by the JMSDF. Japan ultimately plans to procure 23 MQ-9Bs.
The AEW radar reportedly being considered for the MQ-9B is believed to be the podded radar system jointly developed by Saab, the major Swedish defense company, in cooperation with GA-ASI.
This advanced sensor suite consists of two radar pods mounted under the left and right wings of the MQ-9B, enabling near-360-degree surveillance coverage. The system is reportedly capable of detecting aircraft and missiles at ranges exceeding 300 kilometers. Information on detected targets can then be shared with friendly assets and command centers via the Link 16 tactical datalink and satellite communications.
However, as previously noted, the JMSDF originally introduced the MQ-9B primarily as a complementary platform for the P-1 maritime patrol aircraft. Consequently, the mission of conducting airborne early warning and airspace surveillance using AEW radar was not part of the platform’s original operational concept.
Naturally, the MQ-9B would still be capable of conducting maritime surveillance missions while carrying AEW radar pods. Nevertheless, factors such as reduced endurance or the inability to carry maritime surveillance radar simultaneously could potentially affect the aircraft’s primary mission profile.
Given these considerations, discussions may eventually emerge regarding increasing the planned number of MQ-9Bs procured in anticipation of expanded operational roles.
The Future Potential of the MQ-9B within the JMSDF
At present, the P-1 complementary and replacement functions expected of the MQ-9B within the JMSDF primarily refer to peacetime maritime surveillance and monitoring missions around Japan. However, the platform clearly possesses significant potential for future expansion and development.
One such possibility is the acquisition of full-fledged anti-submarine warfare (ASW) capability. GA-ASI has developed a Sonobuoy Dispensing System (SDS) pod capable of carrying up to four pods under the wings of the MQ-9B, and operational testing has already begun with the U.S. Navy. In a 2021 test conducted in a U.S. Navy test range in the Pacific, data collected by sonobuoys deployed from an MQ-9B was transmitted via satellite communications to a ground station, where it was remotely processed. The system successfully obtained real-time tracking data on a simulated submarine target.
Each SDS pod can carry either 10 standard A-size sonobuoys or 20 smaller G-size sonobuoys. Even while carrying SDS pods, the MQ-9B is reportedly capable of remaining airborne for more than 18 hours.
Some observers may take a negative view of the MQ-9B’s ASW configuration due to its disadvantages compared to manned maritime patrol aircraft such as the P-1, particularly in terms of speed and sonobuoy carrying capacity. However, the true significance of the MQ-9B lies not in these superficial performance comparisons, but rather in the synergistic effects the platform can provide.
Currently, both peacetime surveillance missions and wartime ASW patrols must be handled by the P-3C and P-1 fleets. The P-1 requires a crew of 11 personnel, and given Japan’s future demographic decline, maintaining such staffing levels may become increasingly difficult. By contrast, MQ-9B operations require only seven personnel, including aircraft operators and sensor operators, and future integration of artificial intelligence technologies could potentially reduce manpower requirements even further.
