South Korean contractors on Taiwan submarines jailed for leaking documents

Thursday, December 18, 2025 -In a significant and high-stakes ruling, a South Korean court has sentenced defence contractors to prison for leaking classified submarine design information linked to Taiwan’s naval programme. 

The Masan Branch of the Changwon District Court handed down a two-and-a-half-year jail term to a company chief executive and one-and-a-half-year sentences to two employees after finding them guilty of unlawfully sharing sensitive torpedo-launch system designs.

The contractors were involved in supplying components for Taiwan’s submarine project, including torpedo-launching tubes and storage systems. Prosecutors said the defendants transferred documentation containing highly confidential technical details without proper export authorization. 

The court warned the case had the potential to become a major diplomatic burden for South Korea, highlighting the serious national security and geopolitical implications surrounding the leak.

The verdict reflects South Korea’s hard-line stance on the unauthorized export of strategic defence technology, which requires strict approval from the Defence Acquisition Program Administration. 

While the individuals and firms were not publicly named, the ruling sends a clear message that breaches of military confidentiality will be met with severe punishment, especially amid heightened regional tensions over security and defence cooperation.