Taiwan completed the maiden underwater sea trial for its first domestically developed submarine on Thursday, a big milestone in a project aimed at strengthening deterrence against the Chinese Navy and protecting vital sea lanes in the event of war.
Taiwan, which China claims as its own territory, has made the indigenous submarine programme a key part of an ambitious project to modernise its armed forces as Beijing stages almost daily military exercises to assert its sovereignty claims.
The submarine programme has drawn on expertise and technology from several countries, including the US and Britain, a breakthrough for diplomatically isolated Taiwan, whose government rejects Beijing's territorial claims.
Taiwan's CSBC, which is leading construction of what is eventually planned to be eight submarines, said in a statement late on Thursday that the first ship, named the Narwhal, had completed its first underwater test at sea.
It said the submarine had carried out a "shallow-water submerged navigation test".
"Submarines are a key strategic capability with deterrent power," it said, after the test off the southern Taiwanese port of Kaohsiung.
The Narwhal had been due to be delivered to the navy in 2024, joining two existing submarines purchased from the Netherlands in the 1980s, but the programme has been hit with delays.
"Due to constraints in the international environment and pressure from the Chinese communists, Taiwan's indigenous submarine programme has faced various difficulties and challenges from the beginning to the present," CSBC said.
Taiwan has said it hopes to deploy at least two such domestically developed submarines by 2027, and possibly equip later models with missiles.
The first submarine, with a price tag of TW$49.36 billion ($1.58 billion), will use a combat system by Lockheed Martin and carry US-made Mark 48 heavyweight torpedoes.
Taiwan's armed forces are dwarfed by those of China, which has three operational aircraft carriers and ballistic missile submarines and is developing stealth fighter jets.
Taiwan is modernising its military to be able to fight "asymmetric warfare," using mobile and agile systems like submarines, drones and truck-mounted missiles to fend off its much larger adversary China.
Taiwan President Lai Ching-te announced in November 2025 that his government would spend an additional $40 billion on defence.
(Reporting by Ben Blanchard; Editing by Christian Schmollinger)
