By Chelsea Robin | 2026-07-02

Exercise Rim of the Pacific (RIMPAC) 2026 is bringing together 30 nations as the United States marks the 250th anniversary of its founding, with naval forces testing live-fire strike and undersea capabilities during the world's largest international maritime exercise.

The 30th iteration of RIMPAC kicked off June 24 in and around the Hawaiian Islands. It brought together more than 30,000 personnel from 30 nations through July 31.

More than 30 surface ships, more than 206 aircraft, five submarines and 15 national land forces and 206 aircraft are participating in the biennial exercise.

RIMPAC includes traditional maritime training such as amphibious operations, anti-submarine warfare and air defense operations. This year's drills also feature precision fires and a live-fire sinking exercise.

Ship-sinking drills

With such a large participating force, extensive advance planning begins years before the exercise, according to the U.S. Navy. The Naval Supply Systems Command Fleet Logistics Center (NAVSUP FLC) Pearl Harbor is coordinating logistics to support participating forces, including the exercise's Sinking Exercise (SINKEX).

A SINKEX uses live fire from naval and air forces to test weapons and tactics by deliberately sinking decommissioned or obsolete ships. The participants intend to sink the ex-USS Mobile Bay (a guided missile cruiser) and ex-USS Peleliu Bay (an amphibious assault ship), according to the TWZ news site.

"When people watch SINKEX, they'll see ships, aircraft and weapons systems working together," said Cmdr. David Francia, director of operations at NAVSUP FLC Pearl Harbor. "What they may not see are the logisticians working behind the scenes to ensure those units have the fuel, supplies and support they need to be there."

The exercise "demonstrates the interoperability and collective strength that underpin regional security and maritime stability throughout the Pacific," the U.S. 3rd Fleet said in a June 26 statement. It "provides participating nations an opportunity to validate tactics, techniques and procedures while exercising command-and-control capabilities in a multinational environment."

Undersea warfare

Submarine forces under Commander, Submarine Force, U.S. Pacific Fleet (COMSUBPAC) are using realistic at-sea training scenarios to strengthen undersea operations, the U.S. 3rd Fleet said in a June 25 statement. The exercise features advanced unmanned undersea vehicles (UUVs) and long-range fires.

"COMSUBPAC units will integrate with cutting-edge UUV capabilities to extend the reach and persistence of undersea intelligence, surveillance and reconnaissance," the statement said.

"This demonstration leverages unmanned systems as force multipliers, enabling manned platforms to operate with greater stealth, lethality and efficiency."

COMSUBPAC submarines are firing UGM-84 Harpoon antiship cruise missiles, demonstrating the ability "to deliver lethal effects against surface threats from standoff ranges, while protecting critical assets," according to the statement.

S. Korea leads

South Korea is serving as the exercise's maritime component commander for the first time. It marks the first time in RIMPAC's 55-year history that an Asian navy has assumed the role. The multinational command team includes senior officers from Chile, Japan and Canada.

South Korean media said the appointment, together with the country's expanded participation in this year's exercise, reflects Seoul's growing role in regional security cooperation.

The aircraft carrier USS Theodore Roosevelt hosted an international helicopter warfighter exchange on June 27, bringing together more than 45 aviators from partner nations to compare operating procedures, discuss aviation challenges and strengthen interoperability, according to the U.S. 3rd Fleet.

RIMPAC has grown steadily over the past decade as the United States and its allies bolster security cooperation in response to China's growing military presence and maritime activities across the Indo-Pacific. The exercise has become a key platform for multinational training and interoperability among countries across the Pacific.

RIMPAC "continues to be the world's premier multinational maritime training event, bringing together allies and partners committed to strengthening security and stability across the region," U.S. Navy Vice Adm. Jeff Jablon, commander of the Combined Task Forces for RIMPAC 2026, said in a statement.

"By training together in complex, realistic scenarios, participating nations improve readiness, sharpen warfighting skills and strengthen the interoperability required to operate effectively alongside one another whenever and wherever needed."