Taiwan's first indigenous submarine completes maiden underwater trials

Taiwan's first indigenous submarine seen here during its sea trials in January 2026. (CSBC)

Taiwan's first domestically built submarine, Hai Kun , has completed its first underwater trials.

CSBC Corporation, Taiwan, the vessel's builder, announced on 29 January that the trials were completed successfully despite the programme facing various challenges since its inception.

No elaborations on these challenges were given in the announcement.

CSBC first announced on 26 January that it was preparing the submarine for its maiden underwater tests and that these preparations are being carried out under the supervision of the Republic of China Navy (RoCN) and foreign technical advisers.

Further trials on the submarine and its systems will continue in partnership with these stakeholders, the shipbuilder added.

CSBC first unveiled Hai Kun in September 2023, describing it as the country's most significant indigenous defence achievement in decades.

The boat is the first of an expected class of eight intended to modernise Taiwan's undersea deterrent at a time of heightened tensions with Beijing.

Although details of the vessel have yet to be revealed, Hai Kun is estimated to measure around 70 m in length with a displacement of about 2,500 tonnes.

While it inherits the main form factor of Taiwan's older Hai Lung-class submarine, the newer boat features several enhancements in its design, including cross‑form rudders for improved manoeuvrability in shallow waters.

Hai Kun is expected to be armed with Mk 48 Mod 6 heavyweight torpedoes and tube‑launched UGM‑84L Harpoon missiles.

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