Beihai Tunnel was excavated in 1968 (Republic of China Year 57) and is one of the largest underwater tunnel systems built during Matsu's wartime construction era. The grid-pattern waterways total 640 meters in length, and dense tool marks carved by hand are still visible on the rock walls today — a silent testament to the years thousands of soldiers spent hacking through the granite mountainside. Boarding a traditional wooden boat at low tide and slowly entering the tunnel is the most direct way to experience the scale of this Cold War fortification.
What to See at Beihai Tunnel
The tunnel was excavated under the "Beihai Project" at the height of the Cold War, primarily to provide concealed mooring for guerrilla vessels, sheltering them from aerial surveillance and artillery threats. The waterway is 18 meters high and 10 meters wide, with a depth of up to 8 meters at high tide; at low tide, the interior forms an enclosed navigable body of water. The tunnel entrance is hidden between the coastal cliffs of Tieban Village, nearly invisible from the open sea — a perfect embodiment of Cold War military camouflage thinking.
At low tide, visitors can board traditional wooden boats and enter the tunnel, experiencing the echo of sound and the shifting of light within a space almost entirely enclosed by rock. The tool marks on the walls are both uniform and dense — direct evidence of entirely manual excavation, a feat of labor that is hard for modern visitors to fathom. The tunnel closes at high tide; be sure to check the tide schedule before planning your visit to avoid a wasted trip.
How to Get the Most Out of Your Visit
Practical Information
Getting There & Timing
- To reach Nangan, take the Taiwan–Matsu ferry (departing Keelung) or fly (Songshan / Taipei to Nangan). Sailings and flights are easily affected by weather; check official announcements from Taiwan Navigation Co. or the Civil Aviation Administration before departure.
- On Nangan Island, rent a scooter or take a taxi to Tieban Village; the tunnel is about 15 minutes by vehicle from Nangan Airport.
- Whether the tunnel is open depends on tidal conditions. Check the Lienchiang County Government Tourism Bureau's announcements in advance or ask on-site.
Nearby Connections
- Iron Fort (Tiebu) is on a reef in the same cove as Tieban Village, reachable on foot — recommended to combine in the same day.
- Renai Village Beach and Dahan Outpost are on the northern side of Nangan and can be added as extension stops on a half-day itinerary.
Source: Lienchiang County Government Tourism Bureau, on-site signage. Photos pending Dio's field photography.