October 3, 2026

Japan, one of the world’s largest operators of Patriot systems, is considering the possibility of transferring anti-aircraft missiles for these air defense systems to Ukraine, but which specific missiles might it transfer, and why might they not be PAC-3 MSE

Itsunori Onodera, a former Japanese defense minister and current member of the Japanese Diet representing the ruling Liberal Democratic Party, said that Japan is considering supplying Ukraine with anti-aircraft missiles for its Patriot air defense systems.

However, it won’t be that simple due to restrictions under Japanese law, which historically imposed strict limits on arms exports but have been gradually eased in recent years. Itsunori Onodera discussed this in a comment to RBC Ukraine.

From Defense Express we would like to note that understanding what this potential supply could involve requires first determining which Patriot missiles are being discussed. Japan is one of the world’s largest operators of the Patriot air defense system, with 24 fire units, ranking second or third behind the United States and Saudi Arabia, and is also the only country in the world where production of PAC-3 MSE missiles has been localized.

However, even though Japan produces its own PAC-3 MSE missiles, it may decide to transfer entirely different missiles to Ukraine. It is known that Japan has PAC-3 MSE missiles in its arsenal, as well as older PAC-3 CRI and PAC-2 GEM variants.

It appears that Japan has a significant number of PAC-3 CRI and PAC-2 GEM missiles in storage. Therefore, Japan may transfer its older missiles to Ukraine while retaining the more modern PAC-3 MSE missiles for its own use. However, it is worth taking a closer look at the PAC-3 CRI and PAC-2 GEM.

The PAC-2 GEM is the oldest missile in Japan’s Patriot arsenal, although they have undergone maintenance. Originally, the PAC-2 GEM was a modernized version of the PAC-2 missile, designed to improve its capability to intercept ballistic missiles.

However, the PAC-2 GEM proved ineffective against ballistic targets, leading to the development of the better-known PAC-2 GEM-T variant, which is still in production today. In this variant, the missile’s nose section was completely redesigned, the fuze was optimized for engaging ballistic targets, and the seeker’s sensitivity was increased.

Even this was not enough to effectively intercept ballistic missiles, so the PAC-3 was subsequently developed, followed by the upgraded PAC-3 CRI variant, which is also stockpiled in Japan. The PAC-3 MSE was subsequently introduced as an improved variant of the PAC-3 CRI, featuring enhanced maneuverability and a 50% increase in range thanks to a new engine.

So, which of these missiles could potentially be transferred to Ukraine? This makes PAC-3 CRI missiles a more likely option, since PAC-2 GEM missiles, although less effective against ballistic targets, are well suited for engaging aerodynamic targets such as aircraft and cruise missiles.

However, it is not yet known whether Ukraine will actually receive PAC-3 CRI missiles. It is also unclear whether Japan will be able to lift the relevant export restrictions in time for the winter and deliver the missiles to Ukraine. For now, all that remains is to wait for the next steps from the Japanese and Ukrainian governments.

https://en.defence-ua.com/news/japan_is_considering_supplying_patriot_missiles_to_ukraine_what_missiles_could_these_be_why_pac_3_mse_is_not_certain-19980.html