The Indonesian Navy has confirmed that its newest offshore patrol vessel, KRI Prabu Siliwangi-321, successfully completed its first sea trial in Italian waters on January 8, 2026, marking an important milestone in the ship’s transition from commissioning to operational readiness. The trial followed the vessel’s formal commissioning in December 2025 and represented the first time the ship sailed under the Indonesian flag with a fully assigned Indonesian crew.
According to the Navy, the initial sea trial focused on familiarization, system verification, and crew integration rather than performance certification. Conducted shortly after departure from facilities associated with Italian shipbuilder Fincantieri, the activity took place in waters routinely used by the Italian Navy for training and testing. The ship had previously served with the Italian Navy under the name Ruggiero di Lauria (P435) before being transferred to Indonesia as part of a broader defense procurement agreement.
The January 8 sailing was described as a foundational step in preparing the vessel for further trials and eventual long-distance deployment to Southeast Asia. Indonesian naval officials emphasized that the objective was to establish baseline operational routines, confirm the functionality of core systems under real sea conditions, and begin building cohesion among the newly formed crew. Additional sea trials are planned in the coming months before the ship departs Italy for Indonesia.
This sea trial marked the first occasion on which the Thaon di Revel–class offshore patrol vessel sailed with its Indonesian crew following commissioning on December 22, 2025. While the ship had previously undergone construction and acceptance activities under Italian supervision, the January trial was framed as the first practical exercise in Indonesian command and control of the platform.
The ship was commanded during the trial by Colonel (Navy) Kurniawan Koes Atmadja, who has been appointed as the inaugural commanding officer of KRI Prabu Siliwangi. Before departure, Colonel Kurniawan led a comprehensive briefing for all embarked personnel, outlining safety protocols, watchstanding assignments, and the sequence of activities to be conducted at sea.
Naval sources indicated that the briefing placed particular emphasis on risk management, internal coordination, and adherence to standardized operating procedures. With many crew members operating the vessel at sea for the first time, attention was given to ensuring clarity of roles across the bridge, engineering spaces, and supporting departments. The preparation phase was intended to minimize uncertainty and reinforce disciplined routines during the ship’s initial sailing.
During the voyage, trial activities concentrated on the verification of the ship’s primary systems, beginning with propulsion and steering. The vessel was operated at various speeds to assess responsiveness, vibration levels, and coordination between propulsion control systems and navigation functions. Maneuvering exercises were conducted to familiarize bridge teams with the ship’s handling characteristics, particularly during course changes and speed transitions.
Navigation systems were tested under operational conditions to validate procedures for situational awareness, plotting, and bridge teamwork. Internal communication systems were also exercised to ensure reliable information flow between compartments, engineering control spaces, and command positions while the ship was underway. The Indonesian Navy stressed that these checks were intended to confirm baseline functionality and crew understanding rather than to certify final performance benchmarks.
Officials characterized the trial as a “learning phase,” designed to expose the crew to integrated ship operations rather than isolated drills. By operating propulsion, steering, navigation, and communications simultaneously, the Navy aimed to develop an early understanding of how individual systems interact during real-world sailing.
At the conclusion of the trial, Colonel Kurniawan conducted an internal evaluation with senior officers and department heads. The preliminary assessment reportedly indicated satisfactory early performance by the crew, while acknowledging that additional sea time would be required to consolidate proficiency and refine procedures. The commanding officer noted that the January sailing represented the first step in a longer readiness process that will include further trials before the ship is assigned routine operational tasks.
The announcement of the sea trial coincided with renewed statements from Indonesian Navy Chief of Staff Admiral Muhammad Ali, who reiterated that continuous modernization of major naval platforms remains a core policy objective. Admiral Ali emphasized that the introduction of new ships such as KRI Prabu Siliwangi should be viewed within the broader context of maintaining sovereignty and maritime security across Indonesia’s vast archipelagic waters.
Rather than focusing on individual acquisitions, the Navy’s leadership has highlighted phased integration and structured training as essential components of modernization. In this framework, commissioning marks the formal entry of a ship into service, while sea trials serve as the critical transition toward operational employment. Readiness, Admiral Ali noted, is derived from the alignment of platform capability and crew competence, with trials acting as the mechanism that brings the two together.
KRI Prabu Siliwangi-321 was originally built for the Italian Navy as Ruggiero di Lauria (P435) by Fincantieri at its Muggiano shipyard in La Spezia. Steel cutting for the vessel took place on April 7, 2021, and it was launched on October 10, 2023, as part of Italy’s Pattugliatore Polivalente d’Altura (PPA) program.
Indonesia acquired the ship under a €1.18 billion contract signed on March 28, 2024, which covers two vessels of the class. The acquisition is financed through a €1.25 billion loan arrangement with European financial institutions concluded in late 2024. The ship was formally renamed KRI Prabu Siliwangi on January 29, 2025, upon handover to Indonesia, and subsequently commissioned in December 2025.
Following the completion of training and trial activities in Italy, the ship is scheduled to undertake a long-distance voyage to Indonesia, where it will enter active service with the Indonesian Navy.
The Thaon di Revel class, also known as the PPA program, was developed by Italy in the 2010s as part of a comprehensive fleet renewal initiative. Launched under Italy’s 2014 naval law, the program sought to replace multiple legacy frigate, corvette, and patrol ship classes with a single standardized hull capable of fulfilling a wide range of missions.
The design emphasizes endurance, automation, and adaptability, allowing ships to be produced in several configurations—Light, Light+, and Full—while sharing the same hull, propulsion architecture, and core systems. This modular approach enables vessels to enter service with limited armament and sensors and to be upgraded later without major structural changes. The class also introduced a large mission bay, flexible internal spaces, and reduced crew requirements compared with earlier Italian surface combatants.
In its current Light+ configuration, KRI Prabu Siliwangi displaces approximately 4,994 tonnes at light load and up to 6,270 tonnes at full load. The ship measures 143 meters in length, with a beam of 16.5 meters, providing substantial internal volume for mission systems and future upgrades.
Propulsion is provided by a combined diesel and gas (CODAG) system, consisting of one 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 operations. Power is transmitted to two controllable-pitch propellers, enabling flexible performance across a wide range of speeds.
The vessel is equipped with a 127 mm main gun, a 76 mm Strales gun, and remote weapon stations. Missile and torpedo systems are fitted for but not with, reflecting the Light+ configuration’s emphasis on patrol and presence missions. The ship features a Leonardo combat management system and integrated sensors, along with aviation facilities capable of supporting one AW101 helicopter or two AS565 helicopters.
Indonesian officials have indicated interest in upgrading the ship to the Full configuration after initial service entry, potentially adding advanced weapons and sensors as operational requirements evolve.
With its first sea trial completed, KRI Prabu Siliwangi now enters a phase of continued testing, training, and refinement before its journey to Indonesia. The Indonesian Navy views the January sailing as a practical starting point in transforming a newly commissioned platform into an operational asset, emphasizing that readiness is achieved through measured progression rather than immediate deployment.
As Indonesia continues to modernize its fleet amid growing regional maritime challenges, the integration of large, flexible platforms such as the Thaon di Revel–class patrol vessels underscores Jakarta’s focus on endurance, adaptability, and sustained presence across its maritime domain.
