Taiwan’s New Submarine Passes a Key Dive Test in a First Undersea Trial

Advanced | February 7, 2026

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Taiwan submarine undersea trial: A Big Step Below the Surface

Taiwan says its first domestically built submarine has completed its first undersea test, a milestone for a program designed to strengthen deterrence and protect vital sea lanes if conflict erupts. Taiwan’s state-owned shipbuilder CSBC said the prototype submarine—known as Hai Kun (also called “Narwhal”)—successfully carried out a shallow-water submerged navigation test near the southern port city of Kaohsiung. (Reuters)

Why This Test Matters

A submarine doesn’t need to fire a shot to matter. Its value comes from being hard to track, which can complicate an opponent’s planning and raise the cost of aggression. CSBC described submarines as a key strategic capability with deterrent power—especially important as China continues to pressure Taiwan with frequent military activity around the island. (Reuters)

The Plan: Up to Eight Boats

Taiwan has made the indigenous submarine project a centerpiece of its defense modernization. Reuters reported that CSBC is leading construction on a planned fleet of eight submarines, with Taiwan aiming to have at least two of the new boats in service by 2027. Taiwan has also said it may equip later models with missiles, depending on how the program develops. (Reuters)

Delays, Pressure, and Foreign Help

This program hasn’t been smooth sailing. CSBC said the project faced constraints in the international environment and pressure from China, and the first submarine slipped past an earlier delivery target of 2024. Reuters also noted that Taiwan drew on technology and expertise from multiple countries, including the United States and Britain, despite Taiwan’s diplomatic isolation. (Reuters)

What’s Onboard

Reuters reported the submarine’s price tag at T$49.36 billion (about $1.58 billion). It is expected to use a combat system from Lockheed Martin and carry U.S.-made Mark 48 heavyweight torpedoes. Naval News added that CSBC described the January submerged trial as the start of a broader test sequence as the program works toward safe, repeatable submerged operations. (Reuters; Naval News)

What to Watch Next

Expect more testing, not a victory lap. CSBC said the submerged trials would proceed in stages—starting with snorkel-depth testing at about 10–20 meters to verify watertight integrity, underwater balance, stability, and the integration of onboard systems. Janes also reported that preparations and oversight involve the Taiwan navy and foreign technical advisers, which suggests Taiwan is aiming for safe, credible results—not rushed headlines. In practical terms, the Taiwan submarine undersea trial is a “Phase 1” moment—proof it can submerge and navigate safely—before deeper tests and full system evaluations move the program closer to real operational readiness. (Taipei Times; Janes; Naval News)

Vocabulary

milestone (noun) — an important achievement or stage.
Example: The Taiwan submarine undersea trial was a major milestone for the program.
deterrence (noun) — preventing action by making the cost seem too high.
Example: Submarines can increase deterrence because they’re hard to track.
prototype (noun) — the first working model of something.
Example: Hai Kun is the prototype submarine for Taiwan’s new class.
submerged (adjective) — underwater.
Example: The submarine completed a submerged navigation test.
navigation (noun) — the process of planning and controlling movement.
Example: Shallow-water navigation can be challenging near busy ports.
constraints (noun) — limits or restrictions.
Example: International constraints slowed parts of the project.
combat system (noun) — integrated electronics used to detect, track, and engage targets.
Example: The boat is expected to use a Lockheed Martin combat system.
torpedo (noun) — an underwater weapon launched from a ship or submarine.
Example: The submarine is expected to carry Mark 48 torpedoes.
operational (adjective) — ready for real use or deployment.
Example: Taiwan hopes to have at least two submarines operational by 2027.
readiness (noun) — the state of being prepared.
Example: More trials will be needed before full readiness is confirmed.

Discussion Questions (About the Article)

What happened during Taiwan’s first undersea trial, and where did it take place?
Why is a shallow-water submerged navigation test a meaningful milestone?
What are Taiwan’s targets for the number of submarines and timeline?
What challenges and delays has the project faced?
What systems and weapons are expected on the first submarine?

Discussion Questions (About the Topic)

Why do submarines matter in modern defense strategy?
How can “asymmetric” military tools change a country’s security planning?
Should smaller countries build weapons domestically or buy them internationally? Why?
How do international politics affect access to defense technology?
What risks come with escalating military modernization on both sides of a conflict?

Related Idiom

“Below the surface” — not obvious at first, but important.

Example: The Taiwan submarine undersea trial shows what’s happening “below the surface” in Taiwan’s defense strategy.

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This article was inspired by: Reuters (source prompt), with additional details cross-checked via Naval News and Janes, plus added trial-stage detail from Taipei Times.