Indonesia starts sea trials of KRI Prabu Siliwangi offshore patrol vessel in Italy.

The Indonesian Navy announced that the KRI Prabu Siliwangi (321) offshore patrol vessel conducted its first sea trial in Italian waters on January 8, 2026, following its commissioning in December 2025.

On January 10, 2026, the Indonesian Navy announced that the KRI Prabu Siliwangi completed its first sea trial in Italian waters on January 8, 2026, following its commissioning in December 2025. The trial marked the first sailing of the former Italian Navy vessel with an Indonesian crew and focused on initial system operation and preparation for further trials prior to deployment to Indonesia.
Follow Army Recognition on Google News at this link

The Thaon di Revel class, also designated PPA, was developed by Italy in the 2010s as part of a fleet renewal program intended to replace multiple older frigate, corvette, and patrol ship classes with a single standardized hull. (Picture source: Fincantieri)

The trial represented the first time the Thaon di Revel-class offshore patrol vessel sailed with its newly assigned Indonesian crew following its commissioning in December 2025. The activity was carried out in Italian waters after departure from the Fincantieri area toward facilities used by the Italian Navy, as the ship previously served in the Italian Navy under the name Ruggiero di Lauria with the hull number P435 before its transfer. This sea trial was framed as a practical step to begin crew integration, system verification, and procedural alignment ahead of further trials planned before long-distance deployment.

The first sea trial was conducted under the command of Colonel (Navy) Kurniawan Koes Atmadja, appointed as the inaugural commanding officer of the KRI Prabu Siliwangi. Before departure, the commander led a full briefing for all embarked personnel, focusing on safety procedures, allocation of watchstanding duties, and the sequence of activities planned during the trial. Particular emphasis was placed on risk management at sea, internal coordination between departments, and clarity of responsibilities during navigation and machinery operation. The Indonesian Navy indicated that this preparatory phase was intended to ensure that the initial sailing with a new crew followed controlled and standardized routines. The briefing also served to align bridge and engineering teams ahead of live system operation under sea conditions.

During the voyage, testing activities focused on the verification of the ship’s primary systems, beginning with propulsion and steering. The vessel was operated across multiple speed profiles to assess responsiveness, stability, and coordination between propulsion control and navigation. Maneuvering exercises were carried out to evaluate handling characteristics and to familiarize bridge teams with the ship’s behavior during course changes. Navigation systems were exercised under operational conditions to confirm procedural accuracy and situational awareness workflows. Internal communications were also tested to ensure reliable coordination between compartments and command positions while the ship was underway. These checks were intended to confirm baseline functionality rather than certify final performance.

The Indonesian Navy described the first sea trial as a structured learning phase for the newly formed crew, emphasizing direct operation of the vessel rather than isolated drills. The objective was to build an integrated understanding of ship handling, where propulsion, steering, navigation, and communications are executed as a coordinated process. At the conclusion of the sailing, the commanding officer conducted a preliminary internal evaluation, highlighting that the trial represented an initial step in a longer readiness sequence. The assessment indicated satisfactory early performance by the crew, while underlining the need for further sea trials to consolidate proficiency. Additional trial periods are planned before the ship is considered ready for routine tasking.

In parallel with the sea trial announcement, Indonesian Navy Chief of Staff Admiral Muhammad Ali reiterated that the continuous modernization of major naval platforms remains a standing policy objective. He linked this approach to maintaining sovereignty and security across Indonesia’s maritime domain, rather than to a single acquisition. The statement positioned KRI Prabu Siliwangi-321 within a broader effort to introduce new platforms through phased integration and structured training. In this framework, initial sea trials are treated as a necessary transition between commissioning and operational employment. The emphasis was placed on readiness derived from both platform capability and crew competence, with trials serving as a key mechanism to align the two.

The KRI Prabu Siliwangi-321, originally known as Ruggiero di Lauria (P435), was built by Fincantieri at its Muggiano shipyard in Italy. Construction began with steel cutting on April 7, 2021, and the ship was launched on October 10, 2023, originally as Ruggiero di Lauria for the Italian Navy. Indonesia acquired the vessel as part of a €1.18 billion contract signed on March 28, 2024, covering two ships of the class, financed through a €1.25 billion loan arrangement with European financial institutions concluded in late 2024. The ship was renamed KRI Prabu Siliwangi on January 29, 2025, handed over to Indonesia, and commissioned on December 22, 2025. It is scheduled to arrive in Indonesia after completing training and trial activities in Italy.

The ship belongs to the Thaon di Revel class, a family of large offshore patrol vessels developed by Italy in the 2010s as part of a fleet renewal program intended to replace multiple older frigate, corvette, and patrol ship classes with a single standardized hull. The program, also designated as PPA for Pattugliatore Polivalente d’Altura, was launched under Italy’s 2014 naval law, which sought to reduce fleet fragmentation while increasing endurance, automation, and adaptability. Construction of the first unit began in 2017, with the class designed from the outset to be produced in several configurations, namely Light, Light+, and Full, sharing the same hull, propulsion architecture, and core systems. This design choice allows ships to enter service with limited armament and sensors, then be upgraded later without structural modification. The class introduced a large mission bay, modular spaces, and reduced crew requirements compared to earlier Italian surface combatants.

In its current Light+ configuration, the KRI Prabu Siliwangi displaces 4,994 tonnes at light load and 6,270 tonnes at full load, with an overall length of 143 meters and a beam of 16.5 meters. Propulsion is provided by a CODAG system combining a General Electric LM2500+G4 gas turbine rated at 32,000 kW, two MTU 20V 8000 M91L diesel engines rated at 10,000 kW each, and electric motors for low-speed operation, driving two controllable-pitch propellers. The ship is armed with a 127 mm main gun, a 76 mm Strales gun, and remote weapon stations, while missile and torpedo systems are fitted for but not with. It carries a Leonardo combat management system, integrated sensors, and aviation facilities for one AW101 or two AS565 helicopters, with Indonesia indicating interest in a future upgrade to the Full configuration after initial service entry.

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.