Taiwan has switched on a fourth undersea cable to the Matsu islands, a win for the outlying islands' internet resilience and for Taiwan's defenses against cable sabotage near China.

• The new 300-kilometer cable links Taiwan's main island to Matsu's Dongyin, Nangan, and Xiju islands, lifting total capacity to about 1.9 Tbps.
• It joins two older cables, microwave links, and satellite terminals to form a layered backup system — Matsu lost every cable twice in recent years, but the second time stayed online thanks to microwave and satellite backups.
• Cable breaks happen 7–8 times a year, mostly from ship anchors and bottom trawling; Taiwan now treats each cut as a national security matter, with tougher penalties and seizure of offending vessels.
• The new cable is double-armored and buried 2.5 meters deep, with an AI and ship-tracking early-warning system run with the Coast Guard; repair times are being cut from 108 days to 64–86.
• Satellite backups now include OneWeb and SES terminals, with Amazon Leo service planned from mid-2027.

Outlook: Similar fourth cables to Penghu and Kinmen are due by year-end, extending the multi-layer backup model across all of Taiwan's outlying islands.