Taiwan’s domestically built submarine prototype, the Hai Kun, completed its first submerged trial on 29 January, a modest milestone for a project beset by technical setbacks and public scrutiny. The dive is planned as a staged sequence, beginning with a shallow 50-metre descent intended to validate hull integrity and systems integration before deeper dives are attempted.
The programme’s timeline reads as a long haul: design began in March 2017, construction started in November 2020, the keel was laid in November 2021, and a naming ceremony was held in September 2023. The vessel completed its first afloat manoeuvre in June 2025 and entered sea trials soon after; the single-ship contract sums to roughly NT$37.9 billion. The builder, Taiwan Shipbuilding Corporation (Taichuan), has argued the project has not been unusually slow, even describing the work as relatively brisk.
Taichuan has framed the trial regimen as three discrete phases — dock tests, sea trials and evaluative testing including yard technical assessments and post-delivery operational checks — and warned the public that the schedule could encounter setbacks. The company’s transparency push included a public primer on submarine testing days before the dive, and it confirmed the staged approach: an initial 50-metre shallow dive followed by progressively deeper trials aimed ultimately at a 200-metre submergence.
The programme’s public profile has nonetheless been dominated by earlier technical problems and schedule slippages. Sea trials in mid-2025 exposed issues including pipe leaks, propulsion system faults and other mechanical shortcomings; one early sortie lacked an anchor. Taiwan’s navy acknowledged that the main engine, power management and integrated platform-management systems have not yet been fully tuned, which forced previous trials to remain on the surface.
Those operational shortcomings have fed domestic scepticism. Social-media commentary ranged from wry to hostile, with critics dubbing the vessel a “shallow sub or money sub” and questioning whether a 50-metre test is worth pride given cost and delays. The navy has reportedly levied financial penalties on the builder for missing delivery milestones, while public frustration reflects broader anxieties about defence procurement and project oversight.
The Hai Kun’s progress matters because submarines are central to Taiwan’s strategy of asymmetric deterrence. A credible undersea capability complicates any maritime coercion and offers a relatively cost-effective means of denial. Delays and technical problems therefore have consequences beyond engineering: they blunt Taiwan’s near-term deterrent posture and have political ramifications for the government and defence establishment.
Operationally, the first submerged test is a necessary but insufficient step toward fielding an effective platform. The programme will need sustained systems integration work, repeated successful submergences to operational depths, and crew training before it can be judged operationally useful. Politically, Taipei faces a dual task: fixing technical shortcomings while managing public expectations and demonstrating that domestic defence industrialisation can deliver credible capabilities on reasonable budgets.