Asia Defense | Security | South Asia

RIMPAC 2026 and the Future of Multinational Maritime Operations in the Indo-Pacific

This year’s iteration of the exercise reflects several important strategic concepts – and a focus on countering China’s navy.

Multinational ships sail in formation during Exercise Rim of the Pacific 2026 (RIMPAC 2026) in the Pacific Ocean, July 22, 2026.

The biennial Rim of the Pacific Exercise, or RIMPAC, is one of the most important military exercises in the Indo-Pacific. This year’s theme, “Partners: Integrated and Prepared,” highlights the central purpose of the U.S.-led exercise: strengthening collective defense and multinational operational coordination across the region. 

More specifically, RIMPAC is designed to integrate the operational mechanisms, command procedures, and military systems of the United States and its allies and partners. RIMPAC 2026, which started on June 24 and will conclude on July 31, reflects several important strategic concepts.

Strengthening Undersea Warfare

One of the most important features of this year’s RIMPAC is the emphasis on submarines and anti-submarine warfare aircraft. This reflects growing concern over the expanding carrier and undersea capabilities of the People’s Liberation Army Navy (PLAN).

Since the previous RIMPAC in 2024, China’s aircraft carrier development and operations have drawn increasing international attention. In addition to conducting more frequent maritime exercises in the Western Pacific, China has also introduced new carrier-related aircraft, including newer variants of the J-15 and the J-35. The Liaoning has carried out repeated takeoff and landing training in the East China Sea and the Western Pacific. In 2025, China’s two-carrier operations beyond the First Island Chain and deeper into the Pacific further heightened regional concern over the PLAN’s carrier capabilities. These developments naturally make China’s carrier strike groups a major focus as participating countries seek to integrate and coordinate their operational capabilities during RIMPAC.

At present, the deployment of land-based anti-ship missiles remains an important tactic for the United States and its allies along the First Island Chain. This “using land to control the sea” approach is a practical way to counter the PLAN. However, when it comes to countering Chinese aircraft carriers, undersea attack remains one of the most effective options. Compared with engaging the PLAN through surface anti-ship or air-defense operations, submarines can provide a more survivable and effective means of threatening carrier strike groups.

How to integrate undersea forces for operations against PLAN carrier formations will therefore be one of the key areas of training for the United States and its partners in this year’s RIMPAC. Five submarines are reportedly taking part in RIMPAC 2026, compared to just three in RIMPAC 2024.

Learning From Recent U.S. Combat Experience

Another important aspect of this year’s exercise is the opportunity for participating countries to learn from recent U.S. operational experience, particularly in air defense, counter-drone operations, and responses to unmanned surface vessels in the Middle East.

For the 30 participating countries, RIMPAC is not only an opportunity to conduct joint exercises with the U.S. military and become familiar with one another’s doctrines and new equipment. It is also a platform for system integration and combined personnel training. This is one of the main reasons why countries continue to attach importance to participation in RIMPAC.

In recent years, however, U.S. forces have also accumulated valuable real-world experience in the Middle East. Recent operations have shown that traditional missile defense systems are facing new challenges. The most pressing aerial threat today is no longer limited to aircraft or missiles, but increasingly comes........

© The Diplomat