Indonesia Makes Naval History: KSOT Autonomous Submarine Fires First Torpedo, Joining US, Russia, and China in Elite Underwater Club

(DEFENCE SECURITY ASIA) — Indonesia has etched its name into the annals of naval history with the successful torpedo launch from its domestically developed autonomous submarine, the Kapal Selam Otonom (KSOT), on October 30, 2025.

The test, conducted in the waters of the II Fleet Command (Koarmada II) near Surabaya, East Java, marks Indonesia’s formal entry into the elite circle of nations possessing autonomous underwater strike technology.

With this achievement, Indonesia becomes the fourth country in the world—after the United States, Russia, and China—to design, develop, and operationalize an autonomous submarine capable of independent combat functions.

The launch event was remotely observed by President Prabowo Subianto from Jakarta, while senior figures from the Ministry of Defence (Kemhan), the Indonesian Navy (TNI AL), and PT PAL Indonesia attended on site, emphasizing the operation’s strategic importance.

The milestone not only underscores the KSOT’s operational maturity but also represents a quantum leap in Indonesia’s maritime defense doctrine, aligning perfectly with the nation’s “Global Maritime Fulcrum” vision amid increasing Indo-Pacific tensions.

The torpedo launch was executed under the supervision of Defence Minister Sjafrie Sjamsoeddin, TNI Commander General Agus Subiyanto, and Navy Chief Admiral Muhammad Ali, alongside PT PAL President Director Kaharuddin Djenod.

The operation began with a comprehensive readiness briefing before observation from the helideck of the KRI Soeharso-990.

A lightweight training torpedo—devoid of a warhead—was crane-loaded onto KSOT-002 within 30 minutes, demonstrating the platform’s streamlined re-arming procedures.

Once submerged and under the remote supervision of PT PAL’s Autonomous Submarine Command Centre (ASCC), the KSOT executed surface maneuvers, periscope-depth trials, and variable-speed sequences.

The Piranha torpedo was launched in a semi-submerged state, traveling approximately 250 metres before missing its intended target, though the launch and propulsion systems performed flawlessly.

Admiral Muhammad Ali stated, “The torpedo has successfully exited the launcher. Once equipped with sensors, it will seek its target on its own.”

Minister Sjafrie Sjamsoeddin added, “This is the inaugural launch of the KSOT and the first torpedo firing by our nation’s children at PT PAL… 100% designed by Indonesian children.”

PT PAL’s Djenod confirmed, “Overall, the KSOT torpedo firing test went well.”

The success reinforced Indonesia’s confidence in fielding advanced unmanned subsurface combat systems, a technological stride usually associated with leading global naval powers.

Genesis and Evolution of the KSOT Programme

The KSOT programme was conceived under the Kemhan’s 2022 directive to modernize Indonesia’s defense industry and reduce dependence on imported systems.

PT PAL Indonesia, headquartered in Surabaya, was tasked with developing a next-generation autonomous submarine capable of operating in hostile or GPS-denied waters.

PT PAL’s experience spans work on Scorpène-class submarines with France’s Naval Group and refits of South Korea’s Type-209 Chang Bogo submarines—foundations that accelerated the KSOT’s engineering maturity.

In 2022, PT PAL and Germany’s Diehl Defence signed a Memorandum of Understanding (MoU) focusing on underwater missile production and systems integration, enhancing the KSOT’s indigenous capabilities.

By 2024, the concept evolved rapidly, and after multiple redesigns, the full-scale KSOT-008 prototype debuted at the TNI’s 80th Anniversary Parade on 5 October 2025, a moment that stunned defense observers.

The platform incorporates over 50 percent local content (TKDN), with 100 percent of its design developed by Indonesian engineers, reflecting a major step towards defense industrial sovereignty.

Designed as an Extra-Large Unmanned Underwater Vehicle (XLUUV), the KSOT was developed to fulfill TNI AL’s requirement for cost-effective, low-risk, long-endurance alternatives to conventional manned submarines.

It is a key enabler for maritime monitoring, territorial patrol, and deterrence missions across Indonesia’s archipelagic sea-lanes.

Technical Features and Capabilities

The KSOT-008 displaces 37.28 tons, measures 15 metres in length, 2.2 metres in beam, and 1.85 metres in draught.

It employs lithium-ion battery propulsion for low acoustic signature and long underwater endurance, a hallmark of next-generation submarine design.

The craft cruises at 5 knots, achieves 8-20 knots maximum speed depending on configuration, and boasts an operational range exceeding 6,000 nautical miles.

It can dive to 350 metres and maintain 72 hours of continuous submerged endurance or up to six months in extended remote missions.

The KSOT integrates AI-driven processors for navigation, threat analysis, and decision-making, capable of operating autonomously in GPS-denied environments using Inertial Navigation Systems (INS) and terrain correlation algorithms.

Control is exercised via PT PAL’s ASCC, a mobile satellite-linked ground command unit capable of managing missions up to 200 nautical miles (320 kilometres) from the submarine.

With its AI integration, sensor fusion, and networked command architecture, the KSOT sits alongside international counterparts such as the U.S. Navy’s Orca XLUUV, China’s HSU-001, and Australia’s Ghost Shark.

Variants and Mission Configurations

PT PAL Indonesia has developed three core KSOT variants, each tailored to different operational missions.

The Surveillance Variant is optimized for Intelligence, Surveillance, and Reconnaissance (ISR), featuring high-definition sonar, optical sensors, and seabed mapping tools.

It is designed to monitor maritime traffic, undersea infrastructure, and detect intrusions within Indonesia’s Exclusive Economic Zone (EEZ).

The One-Way Attack (OWA) Variant, also referred to as the “Kamikaze” KSOT, serves as a loitering underwater munition equipped with an explosive payload designed to strike enemy warships or ports in suicide-style missions.

The Torpedo-Launch Variant represents the system’s offensive backbone, capable of carrying up to six heavyweight torpedoes such as Leonardo/Whitehead Black Shark or anti-ship missiles like the MBDA Exocet.

This configuration enables the KSOT to conduct anti-submarine, anti-surface, and standoff strike missions—a true multi-role undersea combatant.

These variants also support mine-laying, electronic surveillance, and swarm operations when linked to manned platforms such as the CN-235 Maritime Patrol Aircraft.

Strategic Outlook and Future Deployment

Following the successful torpedo trial, the Indonesian Ministry of Defence aims to produce 30 KSOT units by 2026, a massive industrial leap valued at approximately US$1 billion (≈ RM 4.8 billion).

The units will be strategically deployed along Indonesia’s critical maritime choke points, including the Sunda, Lombok, and Makassar Straits—key arteries of global trade and naval transit.

Once fully operational under the Submarine Operations Command (Koopskasel), the KSOT fleet will enhance underwater persistence, freeing manned submarines for high-value deterrence roles while the unmanned fleet handles ISR, patrol, and denial missions.

Strategically, the KSOT embodies asymmetric deterrence, providing Indonesia with round-the-clock maritime presence while mitigating risks to personnel.

This development is a pillar of Indonesia’s “Trisula Perisai Nusantara” (Trident Shield of the Archipelago) doctrine, envisioning multi-layered defense across air, surface, and subsurface domains.

Regionally, the KSOT’s entry intensifies Southeast Asia’s undersea arms competition, signaling Indonesia’s technological parity with the region’s more established naval powers.

The potential for defence exports is already under discussion, with the Philippines and Malaysia seen as potential customers for a scaled KSOT variant to reinforce their EEZ defense capabilities.

Geo-Strategic and Military Analysis

The KSOT program’s significance extends far beyond a single torpedo launch.

It reshapes Indonesia’s underwater strategic posture at a time when the Indo-Pacific region is becoming the epicenter of a silent undersea arms race.

Major powers—the United States, China, Australia, and Russia—are investing heavily in unmanned underwater vehicles (UUVs) and XLUUVs, each seeking dominance in the “invisible battlefield” beneath the ocean.

Indonesia’s geography, spanning 17,000 islands across 5,000 kilometres, gives it a natural advantage to leverage autonomy and AI for persistent maritime coverage.

The KSOT enables low-cost surveillance and strike operations across these chokepoints, ensuring the security of critical seabed infrastructure, submarine cables, and energy pipelines.

From a technical perspective, the KSOT’s modularity allows payload customization, from torpedo bays to loitering munitions, creating operational flexibility unseen in most Southeast Asian navies.

Its AI-enhanced decision loop reduces operator load, allowing for autonomous engagement decisions based on environmental data and sensor fusion.

Operationally, the KSOT grants the TNI AL a strategic instrument to detect, deter, and deny incursions, especially in disputed or strategically sensitive waters.

In comparison to traditional submarines costing hundreds of millions per unit, the KSOT’s cost-to-capability ratio offers Indonesia a scalable fleet capable of area saturation and persistent presence operations.

Its success also symbolizes a coming-of-age moment for Indonesia’s defense industry—no longer a license producer, but an innovator and exporter in autonomous maritime systems.

For the region, this milestone sets a new benchmark for maritime autonomy, potentially inspiring ASEAN cooperation in unmanned maritime defense networks to safeguard shared sea lanes.

As the KSOT fleet evolves, Indonesia’s maritime defense strategy will likely shift toward distributed operations, AI network integration, and real-time ocean data fusion, all of which align with next-generation naval warfare doctrines.

Conclusion

Indonesia’s first torpedo launch from the KSOT marks a historic and strategic milestone in the nation’s quest for maritime self-reliance.

It signifies the arrival of Indonesian engineering innovation in a field dominated by superpowers and reinforces the archipelago’s resolve to secure its sovereign waters.

As production accelerates and new mission variants mature, the KSOT will transform Indonesia’s underwater operations—from covert ISR missions to autonomous strike capabilities—cementing Jakarta’s role as a rising regional maritime power.

Beyond technology, the KSOT is a statement of intent—that Indonesia’s defense industry is ready to compete on the global stage, shaping the future of autonomous undersea warfare in the Indo-Pacific.

It also demonstrates that Indonesia is no longer content to be a mere consumer of foreign naval technology but is prepared to become a supplier and solutions provider to friendly and like-minded maritime nations.

The successful test will strengthen Jakarta’s bargaining power in regional maritime security dialogues, especially in forums that discuss undersea infrastructure protection, EEZ enforcement, and choke-point surveillance.

The KSOT will provide the TNI AL with a persistent, hard-to-detect, and cost-efficient underwater presence that can be surged in times of crisis without exposing human crews to danger.

In the longer term, this programme will catalyse spin-off technologies—such as autonomous surface vessels, seabed sensor networks, and AI-enabled anti-submarine warfare nodes—that can be exported for additional revenue and strategic influence.

It will also encourage deeper trilateral and minilateral defence-industrial cooperation between Indonesia and regional partners that are similarly seeking affordable unmanned maritime solutions.

Most importantly, the KSOT proves that with political will, sustained funding, and a clear maritime doctrine, Southeast Asian states can field world-class undersea capabilities without relying entirely on external powers.

— DEFENCE SECURITY ASIA