US Navy sinks decommissioned assault ship USS Peleliu in RIMPAC SINKEX

The US Navy has sunk the decommissioned amphibious assault ship USS Peleliu in a live-fire sinking exercise in the Pacific, employing unmanned surface vessels and anti-ship missiles launched from a submarine.

Exercise Details

The Tarawa-class ship (hull number LHA 5) was targeted on 17 July during Exercise Rim of the Pacific (RIMPAC) 2026. Footage released by US 3rd Fleet showed unmanned surface vessels engaging the hulk, which was also struck by two UGM-84 Harpoon anti-ship missiles fired from the Los Angeles-class fast-attack submarine USS Columbia.

About SINKEXs

Sinking exercises, known as SINKEXs, allow navies to test weapons against full-sized targets. They are a regular feature of RIMPAC and provide a means of disposing of decommissioned hulls. A single target is often engaged by multiple platforms—including ships, aircraft, and submarines—using missiles, torpedoes, and gunfire.

Under US environmental regulations, such exercises must be conducted in water at least 6,000 feet deep and at least 50 nautical miles from land. Vessels are cleaned of hazardous materials before being sunk.

USS Peleliu: Service History

• Served for more than 35 years
• Displacement of nearly 40,000 tons
• Launched a variety of aircraft from its flight deck
• Conducted combat operations and humanitarian missions across half the globe
• LHAs are the largest of all amphibious warfare ships and resemble small aircraft carriers
• Decommissioned in 2015 as the last of the Tarawa class
• Named after the 1944 Battle of Peleliu

RIMPAC 2026 Overview

The exercise involves:

• 30 nations
• 30 ships
• 5 submarines
• 15 national land forces
• More than 190 aircraft
• More than 30,000 personnel

Operations are taking place in and around the Hawaiian Islands from 24 June to 31 July. The US Navy describes RIMPAC as the world's largest international maritime exercise, providing training opportunities while fostering cooperative relationships and supporting the safety of sea lanes. RIMPAC 2026 is the 30th exercise in a series that began in 1971.

Second SINKEX of the Exercise

The Peleliu sinking was the second of two SINKEXs at this year's exercise. Five days earlier, on 12 July, the decommissioned Ticonderoga-class guided-missile cruiser USS Mobile Bay (CG 53) was sunk in the same waters. Both ships now rest on the Pacific seafloor, roughly 15,000 feet down and more than 50 nautical miles off the northern coast of Kauai.

During the two exercises, units from Australia, Canada, Italy, Japan, New Zealand, and Spain took part in targeting and live-firing alongside US Navy, Air Force, and Army forces.

USS Mobile Bay Service History

Mobile Bay entered service in 1987 and was decommissioned in 2023, having deployed to the Pacific on humanitarian and peacekeeping missions and supported operations in Iraq.

Official Statements

Republic of Korea Navy Rear Admiral Inho Kim, RIMPAC 2026 Combined Force Maritime Component Commander, said:

"The successful execution of multiple SINKEXs highlights the unbreakable bond and growing capability of our coalition."

US Navy Vice Admiral Jeff Jablon, the exercise's Combined Task Force commander, said:

"SINKEXs are a prime example of the strength and readiness our partnerships create."