U.S. Navy ship USS Cincinnati arrives in Indonesia for new joint maritime exercise.

The USS Cincinnati (LCS-20), an Independence-class littoral combat ship of the U.S. Navy, arrived at Batu Ampar Port in Batam, Indonesia, on December 9, 2025, as part of the ASEAN-U.S. Maritime Exercise (AUMX) 2025.

On December 10, 2025, the Indonesian Naval Regional Command IV (Kodaeral IV) announced that the U.S. Navy’s USS Cincinnati (LCS-20), an Independence-class littoral combat ship, arrived in Batam, Indonesia, on December 9, 2025, as part of ASEAN-U.S. Maritime Exercise 2025. The visit initiates coordinated harbor-phase activities before participating naval units transition to combined operations at sea in the Riau Islands region.
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Since entering service in October 2019, the USS Cincinnati conducted operations around Hawaii and Guam, transits and activities in the South China Sea, and port visits and exercises with countries such as Singapore, Malaysia, the Philippines, Timor-Leste, Brunei, and Indonesia. (Picture source: Kodaeral IV)

AUMX 2025 is the second iteration of the ASEAN-U.S. Maritime Exercise (AUMX) conducted under this specific format. The exercise is designed to bring together naval forces from ASEAN countries, such as Indonesia and Vietnam, and the United States within a single, coordinated training structure. Its organization combines shore-based coordination with follow-on operations at sea, allowing participating navies to align procedures, communications standards, and command relationships before conducting combined maneuvers. Batam will serve as one of the key entry points for the exercise, hosting initial activities before ships move onward. The overall framework reflects an emphasis on structured cooperation rather than isolated engagements. Within this context, the exercise supports regular interaction among participating navies operating in Southeast Asian maritime areas.

During the Batam phase, participating naval units enter the harbor phase of AUMX 2025, which serves as the preparatory stage before combined maritime operations. This phase includes coordination meetings between command elements, technical exchanges related to ship operations, and logistical arrangements necessary for sustained activity at sea. Planning discussions focus on navigation procedures, safety coordination, communications alignment, and sequencing of exercise events. The harbor phase also allows crews to conduct checks and adjustments before transitioning to open-water operations. According to the provided information, these activities are explicitly linked to the upcoming sea phase. The maritime portion of the exercise is planned to take place in waters around the Riau Islands region. This sequence from port coordination to maritime operations will form the core operational flow of AUMX 2025.

The Independence-class littoral combat ships (LCS) were developed in the early 2000s as part of a U.S. Navy initiative to develop smaller surface combatants intended for operations in coastal and near-shore environments. The program was launched alongside a parallel design effort, resulting in two distinct hull types, with the Independence-class adopting a trimaran configuration developed from commercial high-speed vessel concepts by Austal. This hullform was selected to emphasize speed, stability, and internal volume rather than traditional destroyer survivability standards. Responsibility for construction was assigned to Austal USA in Mobile, Alabama, under a competitive fixed-price contracting approach. The Independence-class was initially conceived around modular mission packages covering surface warfare, anti-submarine warfare, and mine countermeasures. Over time, operational experience led to a shift away from frequent module changes toward more stable mission assignments for individual ships.

The USS Cincinnati (LCS-20), one of the later Independence-class ships, was ordered as part of the expanded block-buy contracts awarded for the class to Austal USA. The keel was laid in April 2017, followed by launch in May 2018 and commissioning into active U.S. Navy service in October 2019. The ship is the fifth naval vessel to bear the name Cincinnati and is homeported at Naval Base San Diego, California. Following commissioning, it was assigned to Littoral Combat Ship Squadron One. Its service history includes training and deployments in the Pacific Ocean, operations around Hawaii and Guam, transits and activities in the South China Sea, and port visits and exercises with partners in countries such as Singapore, Malaysia, the Philippines, Timor-Leste, Brunei, and Indonesia.

The USS Cincinnati, with its trimaran hull designed for coastal and regional maritime environments, measures 127.4 m in length, with a beam of 31.6 m and a draft of approximately 4.27 m. Displacement is listed at around 2,307 metric tons in light condition and approximately 3,104 metric tons at full load. Propulsion is provided by a combined system of gas turbines and diesel engines driving four waterjets, supplemented by a retractable azimuth thruster and four diesel generators. This arrangement enables sustained speeds above 40 knots, but the USS Cincinnati could also reach higher sprint speeds of up to 47 knots, with an operational range of approximately 4,300 nautical miles at cruising speed (20 knots). A core crew of about 40 personnel operates the vessel, including 8 officers and 32 enlisted, with additional accommodation available for mission-specific or aviation detachments of up to 35 personnel.

The ship’s weapons fit includes a BAE Systems Mk 110 57 mm naval gun as the primary surface armament, supported by four .50 cal (12.7 mm) heavy machine guns for close-range defense (2 aft, and 2 forward). Short-range air and missile defense is provided by an Evolved SeaRAM system equipped with an 11-cell Rolling Airframe Missile (RAM) launcher. The USS Cincinnati's sensor suite includes a Sea Giraffe 3D air and surface search radar, a BridgeMaster-E navigational radar, and an AN-KAX-2 electro-optical and infrared sensor for surveillance and fire control support. Electronic warfare and decoy systems consist of the ES-3601 electronic support measures suite and Mark 36 SRBOC launchers for chaff and infrared countermeasures. The flight deck and hangar support MH-60R or MH-60S Seahawk helicopters, and the class configuration allows for the integration of MQ-8 Fire Scout unmanned autonomous helicopters. Together, these assets extend the ship’s surveillance and operational capabilities, which are certainly going to be used extensively in the incoming AUMX 2025 exercise.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.