South Korea launched its first 3,600-ton-class naval attack submarine, the ROKS Jang Yeong-sil, on October 22, 2025.

The launch ceremony took place at Hanwha Ocean’s shipyard in Geoje, South Gyeongsang Province, where the lead vessel of the Changbogo-III Batch-II programme was unveiled.

The 89-meter-long submarine, named after the renowned Joseon Dynasty scientist Jang Yeong-sil, is larger and more advanced than the previous 3,000-ton-class Dosan Ahn Chang-ho submarines.

It is the first South Korean Navy vessel to feature both lithium-ion batteries and an air-independent propulsion system, allowing it to stay submerged longer and move faster while remaining more difficult to detect.

Officials reported that the submarine includes upgraded combat and sonar systems, improving its ability to process information, detect targets, and engage land-based threats.

The vessel also has ten vertical launch system (VLS) cells for submarine-launched ballistic missiles, up from six in the previous Dosan Ahn Chang-ho-class submarines.

Analysts said the enhancements are designed to strengthen South Korea’s maritime three-axis deterrence system, including the Kill Chain pre-emptive strike platform.

The submarine incorporates a range of domestically developed technologies, including the combat system, sonar, propulsion motor, and lithium-ion batteries, making it a strategic asset for national defence.

Officials said that sound-absorption technologies and other upgrades improve its survivability and operational stability.

Video Credits: Republic of Korea Navy/YouTube

The ROKS Jang Yeong-sil is expected to be delivered to the Navy by the end of 2027, with two more 3,600-ton-class submarines currently under construction.

The launch coincides with South Korea’s goal of becoming the world’s fourth-largest defense exporter, capitalising on growing global demand for its homegrown weapons systems.

Hanwha Ocean has recently been selected as a preferred bidder, along with Germany’s ThyssenKrupp Marine Systems, for a major Canadian submarine procurement project.

The launch also reflects South Korea’s ongoing efforts to strengthen its naval defense capabilities amid growing North Korean military developments, including plans for nuclear-powered submarines.

Analysts say that the enhanced features of the Jang Yeong-sil class allow it to operate more covertly in waters surrounding the Korean Peninsula, increasing its strategic value.

Unlike previous submarine launches, key officials, including President Lee Jae-myung, Prime Minister Kim Min-seok, and Defense Minister Ahn Gyu-back, did not attend the ceremony, which some observers interpreted as a “low-key” approach to avoid provoking North Korea.

Naval officials stated that following the launch, the Jang Yeong-sil will undergo test evaluations before entering active service. The submarine is expected to serve as a core strategic asset, enhancing South Korea’s maritime defence and contributing to regional security.

According to the Navy, the Jang Yeong-sil will undergo test evaluations before its full deployment and will form the backbone of South Korea’s advanced, science-based naval force aimed at safeguarding the country’s maritime sovereignty.

References: yna, koreajoongangdaily