U.S. Indo-Pacific Command and Indonesia jointly co-chaired Exercise Trident Resolve in Banten, Indonesia, with approximately 2,200 personnel from all 19 ASEAN Defense Ministers’ Meeting-Plus countries, INDOPACOM announced on Sept. 24. The exercise ran Sept. 20-26.
The exercise is the largest ADMM-Plus exercise held in a decade, underscoring renewed U.S. commitment to multilateral defense engagement in Southeast Asia, according to INDOPACOM.
Exercise scenarios covered a range of humanitarian assistance, disaster relief and combined military operations. The breadth of participating nations — spanning the 10 ASEAN member states and their nine dialogue partners including the United States, China, Russia, Japan, Australia and India — makes it one of the most inclusive multilateral defense exercises in the world.
U.S.-Indonesia co-leadership of the exercise signals a deepening strategic partnership with ASEAN’s most populous nation at a critical moment in Indo-Pacific competition with China. Indonesia, with a population exceeding 270 million and a strategic position straddling key maritime shipping lanes, is a pivotal partner for American regional strategy.
The ADMM-Plus framework was established in 2010 to promote defense cooperation and build confidence among the diverse group of nations surrounding the South China Sea and broader Indo-Pacific region. The exercises provide opportunities for military forces that may have limited interoperability to train together on common scenarios.
The scale of the 2026 exercise — the largest in a decade — reflects growing demand among ASEAN nations for practical defense cooperation in response to rising tensions in the South China Sea, where China’s territorial claims overlap with those of several ASEAN member states.