South Korean Marine Corps Launches First Marlin High-Speed Combat Boat.

South Korea’s Marine Corps has formally launched the HCB 001 Marlin, its first purpose-built high-speed combat boat, during a ceremony at Gangnam shipyard in Busan on 11 December 2025. The locally designed craft is intended to move Marines faster and with more protection around contested northwestern islands, tightening response times amid persistent tensions with North Korea.

South Korea has taken a visible step in hardening its exposed island defenses, putting the ROK Marine Corps’ first HCB 001 Marlin high-speed combat boat into service during an 11 December ceremony in Busan that defense officials frame as a key milestone in amphibious modernization. Developed under a Defense Acquisition Program Administration effort and built by local yard Gangnam Co., the roughly 18-meter boat combines a domestically produced waterjet propulsion system with an enclosed, partially armored cabin and a remotely controlled weapon station, giving Marines a platform optimised for shallow water sprinting, rapid landings, and emergency extraction from beaches and small piers north of the Yellow Sea.
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The Marlin high-speed combat boat (HCB) has a compact format designed for speed and discretion close to the coast (Picture source: Korean Marine Corps)

The Marlin high speed combat boat (HCB) has a compact format designed for speed and discretion close to the coast. At about 18 metres in length, it has dimensions roughly half those of the navy’s Cheonjungbong-class fast patrol boats, which facilitates manoeuvres near shorelines and access to shallow anchorages. The platform uses a domestically developed waterjet propulsion system that allows a stated top speed of 80 km/h, or more than 43 knots, while maintaining good handling qualities in shallow water. The waterjet reduces draught, protects the propulsion components from debris, and improves acceleration, which is important for rapid approaches and emergency withdrawals in the face of a surface threat or artillery fire.

At industrial level, the Marlin illustrates the growing role of South Korea’s naval sector in the field of specialised small craft. The construction contract was signed with Gangnam Co. in July of the previous year. The build phase began in May, followed by a keel laying ceremony in August, and the official launch took place in December 2025. The schedule provides for a period of trials and evaluations, then delivery to the Marine Corps in December of the following year, with progressive integration into the fleet once all propulsion and combat systems have been accepted. This compressed timeline reflects the authorities’ intention to obtain a fully operational prototype quickly while relying on national expertise in naval architecture and onboard systems.

The Marlin’s armament and protection represent a clear break with the equipment previously used by the Marine Corps. The boat is fitted with a Remote Controlled Weapon Station (RCWS) on the deck, generally armed with a 12.7 mm heavy machine gun, coupled with a stabilised fire control system, electro optical sensors, and a thermal camera for engaging targets by day and by night. Firing can be conducted from inside the cabin, without exposing gunners to small arms fire. Ballistic panels are installed on critical parts of the superstructure to protect the crew and embarked troops against small calibre projectiles and fragments. The enclosed cabin also improves protection against wind, rain, and sea conditions, an aspect often overlooked but important for maintaining personnel effectiveness after a long transit.

Comparison with the older fast semi rigid hull boats, the Rigid Inflatable Boats (RIB), highlights the qualitative change sought. These inflatable units with outboard engines, largely open, offered practically no protection either against enemy fire or against the elements, which limited their prolonged use in rough weather and greatly exposed their occupants during an approach to a beach or jetty. The Marlin introduces a different logic, more focused on survivability and on preserving combat capability on arrival in the area of operations. The cabin also makes it easier to integrate modernised navigation and communication systems, including tactical data links or additional consoles if the Marine Corps decides to install them at a later stage.

The HCB-001 is designed as a mobility multiplier in the constrained environment of the northwestern islands and Korean estuaries. Its maximum speed, combined with good behaviour in shallow waters, is intended to allow the rapid deployment of reinforcements, reconnaissance teams or specialised detachments to island strongpoints or vulnerable coastal infrastructure. The Marlin can approach discreetly, disembark a detachment on a beach or secondary pier, then withdraw before the adversary can concentrate its fire. Employed in flotilla, it offers the possibility of multiplying axes of approach, overloading the adversary’s observation capabilities, and complicating the planning of artillery or long range rocket strikes. In a broader crisis scenario, these fast boats can also act as connectors between major amphibious ships and forward echelons, carrying key personnel, ammunition, or command assets to areas where larger vessels would be too exposed.

The introduction of the Marlin reflects a wider evolution in South Korea’s posture in an increasingly contested regional environment. On the western seaboard, the Northern Limit Line remains disputed by Pyongyang, which conducts repeated naval shows of force and landing exercises. On the eastern coast and further into the Indo-Pacific area, South Korea is seeking to present itself as an actor able to contribute to maritime stability, in line with the United States' presence and the interests of regional partners. By equipping its Marine Corps with a first dedicated vessel, designed and built locally, Seoul sends a message of determination to both adversaries and allies: the defence of forward islands, sea lines of communication and coastal zones no longer depends solely on the navy’s major units, but also on a new generation of fast, protected means tailored to a theatre where a local incident can quickly take on a regional dimension.