'Even if the port is destroyed, we're ready': Inside the US-South Korea floating causeway exercise off Pohang

At noon Wednesday, the beach at Dogu in Pohang — home to the Marine Corps' 1st Division — baked under a summer sun. Beyond the scorching sand, the sea was crowded with chartered civilian vessels, naval ships and landing craft, and a massive floating causeway stretched from the waterline far out to sea like a long gray ribbon. It was, in every sense, a temporary port built on the ocean — conjured by South Korean and US forces to simulate the worst-case scenario: a battlefield with no functioning harbor.

The Combined Forces Command said it was conducting the largest-ever Combined Joint Sustainment Training, or CJST, from Monday through Thursday, deploying more than 4,400 South Korean and US troops and over 600 pieces of equipment.

Brig. Gen. Park Jin-won, CFC's chief of logistics, said the exercise had "maximized sustainment capabilities across all domains — land, maritime and air," adding that logistics capacity is the decisive factor in winning a war. He said the alliance would continue strengthening its combined defense posture through realistic joint training, signaling that the drill aimed not merely at demonstration but at refining combined operational concepts.

CJST is a field training exercise designed to rehearse procedures for smoothly moving personnel, equipment, fuel and supplies in the event of a contingency on the Korean Peninsula — with particular focus on reinforcements and resupply flowing in from the continental United States.

The centerpiece of the exercise was the Combined/Joint Logistics Over-the-Shore, or C/JLOTS, drill — a sub-exercise within CJST. C/JLOTS simulates a wartime scenario in which ports have been destroyed, requiring forces to construct floating causeways and offshore mooring facilities to move supplies ashore. It was the first bilateral maritime logistics over-the-shore exercise in nine years, since 2017.

Frederick Christ, CFC's deputy chief of logistics, said the exercise "demonstrated that the US-South Korea alliance can project combat power through a coastline with no port." He said the drill showed "genuine interoperability for the first time by offloading cargo from a US vessel through a South Korean system." In practice, equipment and supplies unloaded from US ships were brought ashore using the South Korean RATZ system — showing that the two countries' logistics networks can share and operate each other's assets in a real operational environment.

Numerous vessels were mobilized along the Pohang coastline, including chartered civilian crane barges, vehicle-carrying ships and landing craft. Vehicles, equipment, containers and packaged cargo were hauled directly onto the beach via floating causeways and cargo-handling moorings.

What reporters were shown was US military vehicles coming ashore over the American-side causeway, but CFC said the two sides had cross-utilized each other's facilities throughout the exercise.

A CFC official said South Korea's Navy's joint logistics over-the-shore system, introduced last year, was deployed in a CJLOTS exercise for the first time. "US armored vehicles came ashore through the South Korean system, and South Korean supplies were transferred to US transport ships," the official said.

Once supplies and equipment reach the beach, they are moved to a Combat Service Support Area, or CSSA — what the Marine Corps' 1st Division calls its "combat parade ground." A CFC official said the CSSA is equipped with a field hospital, supply warehouses, an on-site repair shop and a space for field engine repairs, including powerpack replacements for tanks.

Normally, broken equipment would be pulled back to the rear for maintenance, but in a contingency it must be fixed on the spot. The use of 3D printers to manufacture critical spare parts was also under discussion.

Anti-drone systems were fully integrated into the exercise for the first time, reflecting the assumption of a persistent drone threat. As drones have come to exert wide influence on battlefields around the world, forces conducted live counter-drone training along the Pohang coast.

Detection radars, jamming equipment and Vulcan cannons were deployed across the Pohang beachhead to defend against enemy drone strikes, showing that the landing site functions not merely as a logistics hub but as a comprehensive sustainment node combining air defense and electronic warfare.

Supplies and equipment were also fitted with concealment covers to hinder drone observation and attack, and the exercise incorporated anti-drone systems including drone guns alongside soft-kill electronic jamming and signal-disruption measures. Beyond the traditional hard-kill approach centered on artillery and autocannons, the exercise was notable for testing a layered, composite counter-drone network — extended into the electromagnetic and sensor domains — in a live operational environment.

Interpretations of the exercise's purpose extend beyond the Korean Peninsula to the broader Indo-Pacific. While the stated focus is on verifying interoperability between South Korean and US systems in the event of a Korean Peninsula contingency, analysts say the drill also reflects US planning for potential emergencies across the Indo-Pacific region.

When reporters asked Kelly Way, commander of the CJLOTS joint task force, whether the exercise was intended not only to deter North Korean provocation but also to check China and Russia, he said C/JLOTS "gives options to all joint force commanders — not just US commanders — to conduct operations without relying on fixed port facilities," adding that it "provides flexibility of movement, in any region, at any time."

He added that "interoperability between South Korean and US forces creates deterrence," and that strengthening the ability to operate together ensures the two sides "can deploy and carry out missions together whenever necessary."

Shin Bum-chul, a senior research fellow at the Sejong Institute, said that answering a question about China and Russia with the phrase "flexibility of movement, in any region, at any time" could be read as an acknowledgment that the exercise contributes to enhancing USFK's strategic flexibility.

However, USFK was explicit in framing the exercise's purpose as the defense of South Korea. A USFK official said C/JLOTS "is aimed at ensuring that South Korea and the United States can work together to defend the Republic of Korea," adding that the exercise "is defensive in nature and focuses on maintaining the readiness to deter aggression and, if necessary, fight and win."