Japan to Assemble AMRAAM Missiles in US Deal, Share SM-3 Know-How
Koizumi and Hegseth agreed in Cebu on AMRAAM assembly in Japan and SM-3 Block IIA data sharing. What the deal covers and what it leaves out.
TOKYO, Oct. 31, 2026 — Japan will host a final assembly and inspection plant for the AIM-120 Advanced Medium-Range Air-to-Air Missile (AMRAAM) under an agreement reached in Cebu, Philippines, on Wednesday, Japan’s Defense Ministry said. Defense Minister Shinjiro Koizumi and Secretary of War Pete Hegseth also agreed to share the technical information needed to raise production of the SM-3 Block IIA ballistic missile interceptor, according to the ministry’s summary of the 30-minute meeting, which was held on the sidelines of the ASEAN Defence Ministers’ Meeting-Plus.
Koizumi called the AMRAAM assembly plant “a groundbreaking agreement that will not only ensure the acquisition of equipment needed by both Japan and the United States, but will also strengthen Japan’s defense industry base,” Breaking Defense reported. Neither government has named the plant’s location, its Japanese industrial partner, an opening date or a production target.
What the two governments actually published
The two readouts differ. Japan’s summary, carried in full by J-Defense News, lists both missile agreements under “Operation Supercharge,” a Japanese initiative to speed up equipment and technology cooperation with Washington. It describes the AMRAAM site as a “final assembly and inspection” (FACO) facility, not a full factory that would build rocket motors, seekers and warheads from scratch.
The Department of War readout does not mention either missile. It says Hegseth “welcomed Japan’s efforts to strengthen its defense industrial capacity” and that “both leaders committed to continue close coordination on critical munitions production.” It also records agreement on “an effective denial defense in the First Island Chain” and on more live-fire training across Japan. RTX, which makes the AMRAAM through Raytheon, referred questions to the Pentagon, Breaking Defense said.
The ministry’s summary adds a second point: Koizumi stressed the importance of shipbuilding and ship-repair cooperation, though no agreement on ships was announced.
Two years from proposal to plant
The idea is not new. At the July 28, 2024 “2+2” meeting of foreign and defense ministers, the two governments named co-production of AMRAAM and the Patriot PAC-3 MSE interceptor as “high-priority efforts” to “expand production capacity” and “meet critical demand,” according to the State Department’s joint statement. That statement set up a missile co-production working group and the Defense Industrial Cooperation, Acquisition and Sustainment (DICAS) forum to study it.
Japan already builds PAC-3 interceptors under license, Stars and Stripes noted, and in 2024 agreed to sell some to the United States. Mitsubishi Electric said in April that it was discussing joint AMRAAM production with Raytheon, Stars and Stripes reported; the ministry has not confirmed which company will run the new line.
Why AMRAAM and SM-3 are in short supply
Both missiles sit on the Pentagon’s list of 14 “critical” munitions picked by its Munitions Acceleration Council this spring. The fiscal 2027 request on that list asks for $1.6 billion to buy 1,006 AMRAAMs (618 for the Air Force, 388 for the Navy) and $2.4 billion for up to 78 SM-3 Block IIA interceptors, Stars and Stripes reported in May. The list followed Operation Epic Fury, the US-Israeli campaign against Iran, which drew heavily on US missile stocks.
The AMRAAM is the radar-guided air-to-air missile carried by the F-35 and other US and Japanese fighters, and it can also be fired from ground launchers. In September, the Pentagon awarded Raytheon a five-year deal worth more than $20 billion that it said would “nearly” double AMRAAM output if Congress provides the money, according to Breaking Defense.
The SM-3 Block IIA, a ship-launched interceptor for ballistic missiles, is already a joint US-Japan program, Breaking Defense noted. Sharing technical data points to more Japanese work on the missile, though neither side has said how much output would rise.
What it means
Analysis: A final assembly line is the first rung of co-production, not the top. It lets Japan check, integrate and certify missiles near the bases that use them, which shortens repair and resupply loops in a crisis. It does not by itself add capacity to make rocket motors, seekers or warheads, and neither readout mentions those parts. Whether this plant raises the total number of AMRAAMs available to both air forces, or mainly moves the final steps to Japan, depends on terms neither government has released.
The timing is also notable. Koizumi told Hegseth that Japan is working to revise its three core security documents, the ministry said, and at the ASEAN meeting he cited three Chinese destroyers and a coast guard ship that crossed the Osumi Strait together this week, a first for that mix of ships, according to AP. Agreements like this one turn the 2024 promise of co-production into a physical site, which is harder to reverse than a joint statement.
Watch for three details: the Japanese contractor chosen, whether the line will also serve export customers, and whether a similar deal follows for PAC-3 MSE, the other missile named in 2024.
Sources
- U.S. Department of War: Readout of Secretary Hegseth’s meeting with Japanese Minister of Defense Koizumi (Oct. 2026)
- U.S. State Department: Joint Statement of the U.S.-Japan Security Consultative Committee (“2+2”), July 28, 2024
- J-Defense News: Japan Ministry of Defense summary of the Koizumi-Hegseth meeting (Oct. 28, 2026, Japanese)
- Breaking Defense: US, Japan reach agreements for AMRAAM assembly, SM-3 production boost (Oct. 2026)
Additional sources
- AP: US and Japan agree to establish a Japanese facility for joint missile production (Oct. 2026)
- Department of War: Hegseth outlines cooperative agenda for regional stability in Asia (Oct. 28, 2026)
