Indonesia has taken a significant step forward in its long-term maritime modernization agenda with the launch of a comprehensive upgrade program for two additional Bung Tomo-class frigates, KRI Bung Tomo (357) and KRI John Lie (358). The modernization effort marks a crucial investment in strengthening the Indonesian Navy’s (TNI-AL) ability to safeguard a sprawling 5.8 million square kilometres of ocean territory and respond to emerging security challenges across the Indo-Pacific.
Announced by defence officials on November 22, the upgrade initiative forms part of TNI-AL’s fleet enhancement roadmap under the Minimum Essential Force (MEF) doctrine, an overarching national defence transformation strategy aimed at achieving full naval capability by 2029. The modernization follows the ongoing mid-life refit of the class’s third vessel, KRI Usman Harun (359), which has been under upgrade since 2020.
Indonesia’s maritime security environment has become increasingly complex in recent years. Illegal fishing syndicates, transnational smuggling networks, and territorial frictions in the Natuna Sea continue to test national resilience. At the same time, assertive manoeuvring by various regional actors has heightened strategic uncertainty in waters pivotal to global commerce.
For TNI-AL, the modernization of the Bung Tomo-class—long considered cornerstone assets in its surface fleet—represents an essential effort to retain credible deterrence and maintain operational readiness across a vast archipelagic theatre encompassing more than 17,000 islands.
“With instability across regional sea lanes and the continued rise of grey-zone coercion, these upgrades guarantee our platforms remain capable of meeting both traditional and non-traditional maritime threats into the 2030s,” one senior naval official said.
The refit program is being executed through a trilateral industrial partnership involving Dutch naval engineering firm Nevesbu, defence systems specialist Thales Netherlands, and Indonesian state-owned electronics contractor PT Len Industri. The collaboration supports Indonesia’s long-term ambition to expand domestic defence manufacturing capacity and reduce reliance on foreign suppliers.
Nevesbu will lead the engineering and structural assessment phase, employing 3D laser scanning to map hull integrity and identify reinforcement needs. Thales Netherlands will integrate the upgraded TACTICOS Combat Management System (CMS), enabling the frigates to operate in a network-centric warfare environment. PT Len Industri will handle local integration, helping Indonesia progress towards its MEF goal of 60% domestic content in naval platforms by 2029.
The Bung Tomo-class began as the Nakhoda Ragam-class—three multi-role light frigates ordered by the Royal Brunei Navy from BAE Systems Marine (now part of BAE Systems Maritime) in a 1995 contract worth £600 million. Built to the F2000 design by Yarrow Shipbuilders, the vessels were highly automated and optimized for small-crew operations, requiring only 79 sailors to run advanced surface and sub-surface systems.
KDB Nakhoda Ragam (now KRI John Lie) and KDB Bendahara Sakam (now KRI Usman Harun) launched in 2001, followed by KDB Jerambak (now KRI Bung Tomo) in 2002. But disputes over performance specifications—especially concerning tropical operational suitability—led Brunei to reject all three ships in 2004.
The vessels remained laid up for nearly a decade until Indonesia seized the opportunity to purchase the entire class in 2012 for roughly £120 million, about one-fifth of the original contract price. After refurbishment, they were commissioned into TNI-AL between July and December 2014 and reclassified as frigates.
Since joining the fleet, the Bung Tomo-class ships have played vital roles in both security and humanitarian missions. KRI Bung Tomo took part in the recovery operation for AirAsia Flight 8501 in 2014, while KRI Usman Harun helped locate the aircraft’s flight recorders using its TMS 4130C1 sonar.
But by the early 2020s, many of the class’s legacy systems had become obsolete. The MBDA Seawolf surface-to-air missile, globally retired in 2018, left a significant capability gap in air defence. Incremental upgrades began with missile enhancements, including the installation of Exocet MM40 Block 3 systems. KRI Bung Tomo received the upgraded missiles in 2024, extending its strike range to 180 kilometres and providing limited land-attack capability. A 2023 live-fire exercise saw KRI John Lie successfully destroy a decommissioned target ship, affirming the frigate’s effectiveness in precision-strike missions.
These improvements laid the groundwork for the broader mid-life upgrade package now being implemented.
The Bung Tomo-class frigates, based on the Yarrow F2000 design, have a standard displacement of 1,940 tons (2,400 tons full load). Measuring 95 meters in length with a 13.4-meter beam and 4.6-meter draught, the ships are well-suited for operations across Indonesia’s narrow straits and complex archipelagic waterways.
Powered by four MAN B&W/Ruston 12RK270TC diesel engines delivering 30.2 MW, they can reach speeds of up to 30 knots and patrol 4,500 nautical miles at 15 knots. Each vessel carries a complement of 107 personnel and features automation-heavy systems designed to reduce crew workload.
The standard armament suite includes an Oto Melara 76mm Super Rapid gun, two 30mm remotely operated weapon stations, two quad Exocet MM40 anti-ship missile launchers, MU90 torpedo tubes, and a helicopter deck and hangar capable of supporting AS565 Panther or similar aircraft.
Sensor systems include the Thales Scout radar, Kelvin Hughes SharpEye radar, and hull-mounted sonar, supplemented by decoy launchers for anti-torpedo and anti-missile defence.
The new modernization package represents a comprehensive leap in combat capability:
TACTICOS CMS integration, allowing real-time data fusion and enhanced decision-making.
SMART-S Mk2 3D radar, capable of detecting threats up to 360 kilometres away.
STIR 1.2 EO Mk2 fire control system, improving precision against air and surface threats.
Vigile Mk2 electronic support measures, strengthening electronic warfare detection and countermeasures.
VL Mica vertical-launch SAM system, replacing the obsolete Seawolf and providing 20 km intercept capability.
Standardization of Exocet MM40 Block 3 missiles across the entire class.
Introduction of Black Scorpion mini-torpedoes, boosting anti-submarine operations.
Propulsion and vibration reduction improvements to enhance endurance and reduce maintenance costs.
Upgrades are expected to be completed between 2027 and 2028, ensuring all three ships remain operationally viable into the next decade.
The modernization of the Bung Tomo-class occurs at a time when Southeast Asian navies are rapidly upgrading their fleets, and external powers are intensifying their presence in the Indo-Pacific.
For Indonesia, the enhancements bolster its capacity to:
Respond to grey-zone incursions near the Natuna Islands.
Counter increased submarine activity by China, Singapore, Vietnam, and Australia.
Participate more effectively in multinational exercises with India, Japan, Australia, and the United States.
Support humanitarian operations in an era of climate-driven maritime disasters.
TNI-AL is projected to operate at least 10 frigates and 26 corvettes by 2030, reinforcing its status as one of the region’s most capable naval forces.
Despite the scope of the modernization, challenges remain. Budget limitations—only USD 1.32 billion allocated to the Navy for 2025—could constrain future acquisitions. Indonesia’s diverse fleet, comprising systems from multiple countries, also requires significant logistical coordination.
Nevertheless, officials view the Bung Tomo upgrades as a cost-effective strategy. They extend the life of proven platforms while meeting immediate operational needs and advancing domestic defence industry capabilities.
The decision to modernize KRI Bung Tomo and KRI John Lie signals Indonesia’s determination to adapt to a rapidly shifting maritime landscape. As regional tensions rise and the Indo-Pacific becomes increasingly contested, the upgraded frigates will enhance Indonesia’s ability to defend its sovereignty, secure vital sea lanes, and project stability across Southeast Asia.
With MEF implementation gaining renewed momentum under President Prabowo Subianto, Indonesia’s frigate modernization marks a decisive step toward a more capable, resilient, and self-reliant naval force—one poised to meet the strategic demands of the years ahead.
