Taiwan's Sword Dragon-class submarines nearing upgrade completion, set for heavy torpedo tests

Taiwan's aging fleet of two Dutch-made Sword Dragon-class submarines is on the cusp of a major transformation. The decade-long "Combat System Performance Improvement Project," initiated in 2018 with a budget exceeding NT$7.4 billion (approximately $230 million USD), is entering its final year.

The core objective of this extensive overhaul is to completely replace the submarines' 30-year-old systems with state-of-the-art digital technology. This upgrade aims to bring the capabilities of the older submarines in line with Taiwan's newly developed Hai Kun-class submarines. The project is a collaborative effort between Taiwan's National Chung-Shan Institute of Science and Technology and Lockheed Martin.

Key enhancements include the integration of a new combat management system, digital optronic periscopes, and advanced sonar. The weapon launch systems are also being digitized to enable precise guidance of U.S.-made MK-48 Mod 6 AT heavy torpedoes and UGM-84L Harpoon anti-ship missiles.

Progress on the upgrade has been steady. The Hai Lung submarine has successfully completed all enhancements and returned to active service. The Hai Hu submarine, undergoing its overhaul concurrently with its maintenance cycle, began work in May 2025 and is expected to finish by the end of this year.

Crucially, the delivery schedule for the MK-48 heavy torpedoes, previously hampered by U.S. supply chain issues, is now clearer. The U.S. will deliver four training torpedoes by the end of 2026. The first batch of 14 live "warhead" torpedoes, essential for combat, is expected to arrive next year, with the remaining 10 to follow the year after. The final validation phase next year will involve live-fire tests of these torpedoes and Harpoon missiles during major military exercises, signifying a new era for Taiwan's underwater defense capabilities.