U.S. anti-ship missiles head to Japan’s westernmost island

The U.S. military will deploy its NMESIS anti-ship missile launcher to Yonaguni, Japan’s westernmost inhabited island and about 107 km (66 miles) from Taiwan, during a major U.S.-Japanese exercise this month, Japan’s Kyodo News reported on Oct. 2, citing the Yonaguni town government.

The launcher will take part in Keen Sword, a large joint exercise held every two years. Japan’s public broadcaster NHK reported that this year’s live field training will start on Oct. 19 and run for 11 days, with both countries bringing their newest ground-based anti-ship missiles, and that it will be the first time NMESIS is deployed on Yonaguni, SBS reported.

Neither government has said how many launchers will go to the island, how long they will stay, or whether any missiles will be fired.

NMESIS, short for Navy-Marine Expeditionary Ship Interdiction System, is a U.S. Marine Corps weapon built on an unmanned Joint Light Tactical Vehicle that carries two Naval Strike Missiles. The missiles can hit ships at ranges of more than 185 km (115 miles), and the remotely driven launcher is designed to move between islands and hide, so it can threaten enemy warships from shore while staying hard to find.

Location of Yonaguni Island, where U.S. Marines will bring NMESIS anti-ship launchers during the U.S.-Japanese Keen Sword exercise in October. Map: The Defence Blog

The system belongs to the 12th Marine Littoral Regiment, a unit based on Okinawa that the U.S. Marine Corps reorganized to defend and hold key islands in a conflict. The regiment formally received NMESIS, along with the MADIS counter-drone system, in June 2026. Its Hawaii-based sister unit, the 3rd Marine Littoral Regiment, was the first to field NMESIS in late 2024 and took it to the Philippines for the Balikatan exercise.

NMESIS first arrived in Japan in July 2025. During the Resolute Dragon exercise that September, Marines moved a launcher to Ishigaki, about 240 km (150 miles) from Taiwan, and displayed it alongside Japan’s Type 12 anti-ship missile at the Japanese base there, though no missiles were fired. Yonaguni is closer to Taiwan still.

Japan has stationed troops on Yonaguni since 2016, when a Ground Self-Defense Force coastal surveillance unit and radar began operating there. Tokyo announced in February 2026 that it plans to place surface-to-air missiles on the island by 2031. The 12th Marine Littoral Regiment has also used the island before, deploying its AN/TPS-80 G/ATOR radar to the Japanese base there during Resolute Dragon in 2024.