Indonesia’s state-owned shipbuilder PT PAL Indonesia successfully conducted a torpedo firing test of its autonomous submarine prototype, the KSOT (Kapal Selam Otomatis Tanpa Awak), on October 30 in Surabaya, East Java. The event marks a significant step in Indonesia’s efforts to strengthen its indigenous defense technology capabilities and bolster maritime security across the vast archipelago.
According to PT PAL, the test was carried out at the Indonesian Navy’s (TNI AL) 2nd Fleet Command pier, where the 324 mm lightweight “Piranha” torpedo, reportedly developed domestically by PT PAL, was loaded into the KSOT’s starboard-side launch tube using a mobile crane. Following the loading procedure, the unmanned submarine maneuvered into deeper waters before successfully launching the torpedo.
A video released by PT PAL later showed the KSOT performing a controlled dive demonstration. Although the prototype remained partially submerged for much of the test, including during the torpedo launch sequence, the event was hailed as a major milestone in Indonesia’s ongoing push toward autonomous underwater capabilities.
The KSOT prototype measures 15 meters in length, with a breadth of 2.2 meters and a draught of 1.85 meters. It can reportedly achieve speeds of up to 20 knots and operate at depths reaching 350 meters. While smaller than conventional manned submarines, the KSOT is designed for a range of missions including surveillance, reconnaissance, and potentially offensive operations.
The full-scale prototype was first unveiled publicly during the Indonesian National Armed Forces’ (TNI) 80th anniversary parade in Jakarta on October 5, 2025, drawing attention for being the country’s first fully indigenous autonomous underwater vehicle (AUV) developed to operational scale.
PT PAL emphasized that the KSOT is fully designed and engineered by Indonesian specialists, with a domestic content level exceeding 50%. The company aims to further increase the use of locally sourced components as the program transitions from prototype to mass production. Commercial off-the-shelf technologies were also integrated into the system to optimize cost efficiency and ensure modular adaptability.
“The KSOT project is not only a technological achievement but also a symbol of Indonesia’s growing confidence in self-reliant defense innovation,” PT PAL said in a statement. The company added that knowledge gained from the KSOT’s development will support future programs, including unmanned surface vessels (USVs) and other autonomous maritime systems.
The torpedo test was attended by Minister of Defence Sjafrie Sjamsoeddin, Navy Chief of Staff Admiral Muhammad Ali, and other high-ranking defense officials. Minister Sjafrie praised the success of the test, calling it “a pivotal step in advancing Indonesia’s naval autonomy and defense industrial base.”
“The KSOT program will continue to undergo testing, refinement, and evaluation. Each stage will improve the system’s reliability and operational effectiveness,” the minister said, noting that the project aligns with the government’s broader vision of modernizing the national defense industry and reducing dependence on foreign suppliers.
Admiral Muhammad Ali added that unmanned underwater systems such as the KSOT will play an increasingly vital role in future maritime defense operations, particularly for intelligence gathering, underwater surveillance, and protecting sea lanes in Indonesia’s exclusive economic zones.
PT PAL has announced plans to deliver 30 KSOT units by 2026, which will be operated by the TNI AL Submarine Operations Command (Koopskasel). These autonomous submarines will be deployed to monitor and secure Indonesia’s strategic maritime choke points, notably the Lombok and Sunda Straits—key transit corridors that are essential for both regional and global shipping routes.
However, PT PAL has not specified whether all 30 units will feature torpedo-launch capabilities. The KSOT platform is modular and can be configured for multiple roles, including intelligence, surveillance, and reconnaissance (ISR), kamikaze or decoy missions, and potentially electronic warfare support.
Given its compact size and design flexibility, the KSOT could also be deployed from larger naval vessels, including frigates or amphibious ships, thereby extending the operational range of Indonesia’s fleet. Analysts suggest that this capability could enable the Navy to conduct distributed undersea operations across the country’s thousands of islands more effectively.
The KSOT program reflects Indonesia’s determination to develop indigenous unmanned defense technologies in response to the rapidly evolving maritime security environment in the Indo-Pacific. With vast territorial waters and strategic sea lines of communication, Indonesia faces growing challenges from illegal fishing, smuggling, and potential incursions into its maritime boundaries.
By fielding a fleet of autonomous submarines, Indonesia aims to enhance persistent underwater surveillance and strengthen deterrence in key maritime zones. The program also positions Indonesia among a small but growing group of nations developing operational unmanned submarine capabilities, alongside the United States, China, Japan, and South Korea.
