TAIPEI (TVBS News) — Taiwan's first domestically built submarine, the Narwhal (海鯤號), completed its maiden underwater dive Thursday morning, a milestone in the island's defense capabilities that came just one day after U.S. Secretary of State Marco Rubio warned that Chinese leader Xi Jinping (習近平) views Taiwan as his personal "legacy project." The submarine descended to depths between 10 and 50 meters in waters off Kaohsiung (高雄), marking a critical step toward the vessel's scheduled delivery to the Navy in June, though the test's success has not yet been officially confirmed by Taiwan's military.
The Narwhal departed from Kaohsiung's Second Port at approximately 11 a.m. local time, escorted by vessels from CSBC Corporation Taiwan (台灣國際造船), the Navy, and port authorities. Military enthusiasts gathered along the harbor, some having traveled from Tainan (台南) as early as 6 a.m., cheering "Go Narwhal! Go Navy! Go CSBC!" as the submarine emerged from the shipyard.
Military observer Chi Yung-yun (紀東昀) said the submarine was expected to conduct tests in designated exercise areas between Kaohsiung Port and Zuoying (左營). The shallow-water tests aim to verify watertightness, underwater stability, and the integration of all shipboard systems, according to CSBC. Senior officials from both CSBC and the Navy were aboard the vessel during Thursday's test.
The test comes amid heightened concerns about Beijing's intentions toward the self-governing island. Testifying before the U.S. Senate Foreign Relations Committee on Wednesday (Washington time), Rubio stated that Xi's ambitions for Taiwan would persist "irrespective of anything that happens in the world." Senator Pete Ricketts had asked whether Washington's Jan. 3 capture of former Venezuelan President Nicolas Maduro might affect China's calculations regarding Taiwan.
Senator Ricketts suggested that, despite the PLA's rapid expansion, its lack of combat experience — compounded by the purge of experienced leaders like Zhang — could make Xi more hesitant to use force. The tactical proficiency demonstrated in the Maduro operation, Ricketts argued, might serve as a deterrent.
The Narwhal represents Taiwan's most ambitious indigenous defense project in decades. CSBC completed three preliminary sea tests on Jan. 26, verifying sonar functionality, propulsion systems, and the underwater odometer — a navigational instrument that measures how far a submarine has traveled underwater and its speed through the water. Following successful shallow-water trials, the submarine will undergo deep-diving tests exceeding 200 meters in waters south of Xiaoliuqiu (小琉球) island.
The submarine program has faced significant delays. Both shallow- and deep-diving tests were originally scheduled for completion before a November 2025 handover to the Navy. Under the contract, CSBC must pay delay penalties of approximately NT$190,000 (US$6,100) per day. The delivery target has since been pushed to June 2026.
The total cost for the Indigenous Defense Submarine (IDS/潛艦國造) program stands at NT$50 billion (approximately US$1.6 billion), though this figure includes torpedoes, naval facilities, and shipyard equipment beyond the submarine itself. The Narwhal's single-vessel contract totals approximately NT$37.9 billion (US$1.21 billion), comprising NT$12.8 billion for personnel, NT$248.4 billion for materials, and NT$117.8 billion for CSBC construction fees.
CSBC has attributed high costs partly to export controls imposed by advanced nations under pressure from Beijing, which have driven up prices for critical navigation and combat systems — referred to as "red zone equipment" (紅區裝備) — that Taiwan cannot manufacture domestically. The company stated that reducing future costs will require accelerating domestic component production and expanding supplier options.
Design work on the Narwhal began in March 2017, with construction commencing in November 2020 and the keel laid in November 2021. The submarine was formally named in September 2023 and completed its first surface navigation test in June 2025. CSBC noted that the 4-year, 2-month construction period from keel-laying to present compares favorably with international benchmarks for prototype submarines, which typically require 6 to 10 years.
Following completion of the diving tests, the Narwhal will enter a technical evaluation conducted by CSBC, which will assess endurance, underwater noise levels, sonar performance, combat systems, and simulated weapons firing using practice torpedoes. The Navy will then conduct tactical evaluations, including live weapons tests, single-ship tactical exercises, multi-ship coordinated operations, and extended patrol readiness assessments.
The submarine program reflects what some defense analysts have called a necessary "paradigm shift" in Taiwan's military strategy. Admiral Lee Hsi-min (李喜明), Taiwan's former Chief of the General Staff, and defense analyst Eric Lee have previously warned that Xi could invade Taiwan "with little warning" to secure his legacy, arguing that Taiwan must fundamentally transform its defense posture. ◼