YOKOSUKA, Japan (September 4, 2026) — The Japan Maritime Self-Defense Force (JMSDF), Republic of Korea Navy (ROKN), Royal Australian Navy (RAN), Royal Australian Air Force (RAAF) and the U.S. Navy successfully completed a Multilateral Anti-Submarine Warfare Exercise (ASWEX) in the Western Pacific, Aug. 25-27, 2026.
The exercise featured three submarines from the U.S. Navy, JMSDF, and ROKN, a RAAF P-8 Poseidon, and a RAN liaison officer supporting from the Commander, Task Force 74 Theater Undersea Warfare Commander's Maritime Operations Center in Yokosuka.
During the exercise, the four nations tested communication pathways and performed tactical maneuvers in close proximity, including tracking exercises, simulated undersea engagements, and joint water space management.
"The success of this exercise is a direct reflection of the trust, shared values, and high level of interoperability among our four nations.” said Rear Adm. Gary Montalvo, commander, Submarine Group 7. “Operating complex undersea assets in close proximity requires absolute precision and robust communication. Working alongside our JMSDF, ROKN, RAN, and RAAF partners in this exercise ensures our forces are ready to respond to any undersea challenge together, reinforcing a credible deterrence to ensure peace, security, and stability throughout a free and open Indo-Pacific."
The exercise provided an opportunity to improve interoperability among the four navies and RAAF, showcasing the capability of their undersea assets and crews to operate multilaterally. ASWEX contributes to enhancing theater undersea warfare coordination and advancing credible deterrence throughout the region.
CSG 7 directs forward-deployed, combat capable forces across the full spectrum of undersea warfare throughout the Western Pacific, Indian Ocean, and Arabian Sea. U.S. 7th Fleet, the Navy's largest forward-deployed numbered fleet, routinely interacts and operates with allies and partners in preserving a free and open Indo-Pacific region.
U.S. 7th Fleet, the Navy's largest forward-deployed numbered fleet, routinely interacts and operates with allies and partners in preserving a free and open Indo-Pacific region.
For more news from Commander, Submarine Group 7, visit www.csp.navy.mil/csg7/