Chunghwa Telecom Announces Completion of the Taiwan–Matsu Fourth Cable: Nearly NT$1.4 Billion, Triple-Route Backup, and 1.9 Tbps

On September 18, 2026, Chunghwa Telecom announced that the “Taiwan–Matsu Fourth Cable,” nearly 300 kilometers long, has successfully completed cable-laying, landing, and testing, and has formally joined Matsu's outbound communications system. Chunghwa Telecom explained that with the Fourth Cable's laying complete, it will form “three mutually backing-up routes” together with the existing Taiwan–Matsu Second and Third Cables, combined with microwave and multi-orbit satellite communications — “three routes” is Chunghwa Telecom's own term. In the same announcement, Chunghwa Telecom also stated that the project cost nearly NT$1.4 billion, linking communications from the main island to Matsu's Dongyin, Nangan, and Xiju.

This article was first fact-checked on September 18, 2026, and updated on October 5, 2026: we re-read the full text of this Chunghwa Telecom announcement, moda's “Latest Submarine Cable Status” page, and the ministry's press release of June 23, 2026, and added the ministry's press release on the 5G applications event it held in Matsu on September 18. This site has not conducted any on-site testing, and offers no advice on whether to travel to Matsu or which telecom carrier to choose. This site previously covered moda's June preannouncement that the project was “coming to completion soon” and the outages and backups of the first half of the year; this article covers only the new facts and differences brought by September's completion announcement, and does not repeat that background.

What Chunghwa Telecom Announced on September 18

What Chunghwa Telecom calls “three mutually backing-up routes” refers to the newly completed Fourth Cable together with the existing Second and Third Cables; the announcement's wording is that the submarine cables linking Taiwan and Matsu are “expanded from two to three, with overall transmission capacity substantially increased to about 1.9 Tbps” — this figure is attached to the submarine cables linking Taiwan and Matsu as a whole, not to any single cable's own capacity. The announcement does not break down each cable's capacity, and this article does not break it down or estimate it either.

Besides the three-route submarine cable setup, Chunghwa Telecom states it has already deployed a 12.6 Gbps Taiwan–Matsu microwave backbone and integrated diverse low-, medium-, and high-orbit satellites, forming what Chunghwa Telecom calls a heterogeneous backup network of “submarine cable, microwave, and satellite”; later in the announcement it also describes the whole setup using the phrase “sea, land, satellite, sky.”

Chunghwa Telecom describes the difficulty of the construction: Matsu is an outlying island with scattered settlements, and sea conditions and construction conditions are complex, with outbound cables having repeatedly suffered external damage in the past — this is Chunghwa Telecom's own account, and the announcement does not list specific incidents, their number, or their cause. Chunghwa Telecom also states that the project will substantially improve Matsu residents' day-to-day communications quality and safeguard the stable operation of the military, police, government, firefighting, medical, education, and public services; these are all Chunghwa Telecom's own claims, and this site has not made any measurements.

From June's “Coming to Completion Soon” to September's “Successfully Completed”: Comparing the Two Official Announcements

A separate article on this site has covered moda's press release of June 23, 2026: the Taiwan–Matsu No. 4 Cable was “coming to completion soon,” without giving a specific date; that press release also forecast that once activated, there would be 3 cables between Taiwan and Matsu, and that Beigan, Nangan, Dongyin, and Juguang Township would each have at least 2 microwave systems for outside communication. Nearly three months later, it was Chunghwa Telecom's turn to issue a completion announcement on September 18, with the wording shifting from “coming soon” to “successfully completed” — but this completion announcement likewise gives no specific commercial-service date or activation date.

Placed side by side, what the two announcements agree on is the number of cables: June's preannouncement said “there will be 3 cables,” and September's says “expanded from two to three.” As for at least 2 microwave systems per township, that appears only in the June press release; September's completion announcement does not restate the number of microwave systems. The four figures — nearly 300 kilometers, nearly NT$1.4 billion, about 1.9 Tbps, and 12.6 Gbps — are ones the June press release did not give and that appear only in September's announcement. The funding source is also stated differently in each: June's moda release says it was built “with Chunghwa Telecom subsidized through the Forward-looking Infrastructure budget,” while September's Chunghwa Telecom announcement itself says “Chunghwa Telecom… invested nearly NT$1.4 billion.” Neither announcement states what share of the total cost the subsidy covers, and this article does not calculate that share either.

How the Backups Stack Up: Three Layers of Cable, Microwave, and Satellite

On how the three routes back each other up, the announcement states, “even if a single route is damaged by a future natural disaster or sudden incident, the other systems can provide immediate support, effectively preventing the risk of an outbound communications interruption” — read in context, “the other systems” includes the submarine cables, microwave, and satellite; the announcement does not state how much traffic the other two cables could each take on if a single route were interrupted. This is Chunghwa Telecom's own claim, not a guarantee, and this site has not tested how it would actually perform after an interruption.

Beyond the three cable routes, there are two more layers of backup: the 12.6 Gbps Taiwan–Matsu microwave backbone, and multi-orbit satellite communications integrating low, medium, and high orbits. Converting 1.9 Tbps and 12.6 Gbps to the same unit and dividing, the former is about 150 times the latter — this is a conversion this article calculated itself; the announcement states the two figures separately, for the cable system and the microwave system, without making this comparison, and it does not state how much traffic microwave or satellite could actually carry if the cables were interrupted.

Here is an example designed by the editors: a reader working in Nangan, Matsu, might want to know, “If a cable breaks again, will communications be affected?” Based on the wording of the announcement as of the fact-check date, the only official statement that can be cited is the earlier sentence, “the other systems can provide immediate support” — Chunghwa Telecom does not specifically state the duration of an outage or its scope. This site has covered, in a separate article, the outages and backups that actually occurred on the Taiwan–Matsu cables in the first half of 2026; the details can be found via the link at the end of this article.

moda's Cable List: Taiwan–Matsu No. 1 Through No. 4, and What It Still Doesn't Say

Chunghwa Telecom's “three routes” refers to the Second, Third, and Fourth Cables; this announcement does not mention the Taiwan–Matsu No. 1 Cable. moda's “Latest Submarine Cable Status” page separately maintains an official cable list; when this article checked it on October 5, 2026, the page stated, “Taiwan currently has 16 international communication cables and 11 domestic communication cables.” The domestic cable list is numbered in order, and entries 2 through 5 are the Taiwan–Matsu No. 1 Cable (TM1-D), Taiwan–Matsu No. 2 Cable (TDM2), Taiwan–Matsu No. 3 Cable (TM3), and Taiwan–Matsu No. 4 Cable (TM4) — all four are on the list. This list is live data that changes as cables are added or removed; checking on a different date, the count and contents of the list could differ.

This list has only three fields — entry number, full Chinese name, and English abbreviation — and no field states which cable is currently in service; Chunghwa Telecom's announcement likewise does not mention the status of the No. 1 Cable. As seen on the fact-check date, the two official documents' statements about “three routes” and “four cables” do not contradict each other, nor do they explain each other. Readers should not infer from this that the No. 1 Cable has been decommissioned or retired, and this article does not make that judgment either.

It is also worth noting that officials themselves use two different names for this cable: searching the full text of the September 18, 2026 announcement, Chunghwa Telecom uses “Taiwan–Matsu Fourth Cable,” and “Taiwan–Matsu No. 4” or “TM4” does not appear; moda's cable list, on the other hand, calls it the “Taiwan–Matsu No. 4 Cable,” abbreviated TM4 — the two refer to the same cable. The landing locations are not written identically either: Chunghwa Telecom's September announcement says “Dongyin, Nangan, Xiju,” while moda's June press release, discussing the microwave system, says “Dongyin, Beigan, Nangan, and Juguang Township” — the two documents are discussing the cable and the microwave system respectively, and the place names themselves are not entirely the same. This article quotes each side's original wording separately, without merging them into a single list.

Chunghwa Telecom's completion announcement itself also leaves plenty of gaps: it only states that it “announced” on September 18 that construction, landing, and testing were complete, without giving an exact completion date, commercial-service date, or activation date; 1.9 Tbps is the “overall transmission capacity,” and the capacity of any single cable, the cable specifications, the number of fiber pairs, the landing-station names, the contractor, and the cable-laying ship are not stated; as for the 12.6 Gbps microwave backbone, it only says it “has also been deployed,” without giving a date. Nor does the announcement give any of latency, availability, actual download speed, or recovery time should a cable break; “substantially improving Matsu residents' day-to-day communications quality” is Chunghwa Telecom's own claim. Whether rates, plans, or application methods for residents will change is not stated in the announcement either.

The Same Day in Matsu: moda and Taiwan's Three Major Carriers Show 5G Applications

On the afternoon of September 18, 2026, moda held a “5G vertical-domain application experience event” in Lienchiang County, where Taiwan's three major telecom carriers each showed a different application scenario. According to moda's press release, Chunghwa Telecom's theme was “AI digital culture technology applications,” combining Matsu's local culture and tourism features; FarEasTone showed “五官鏡” (literally, “five-senses scope”), a 5G smart-healthcare application that captures medical images with devices such as high-resolution otoscopes and laryngoscopes and transmits them in real time over the 5G network so that medical staff can read the images and consult remotely; and Taiwan Mobile, under the theme “Smart Campus智慧校園大可能,” showed smart-campus and interactive-teaching applications.

Minister Yi-Jing Lin (林宜敬) said in the press release that the real value of 5G is bringing convenient digital services into daily life through high bandwidth and low latency combined with AI. The press release also says “as the Taiwan–Matsu No. 4 Cable is completed and activated and 5G and other digital applications gradually take root,” describing the cable as “completed and activated” but giving no date. The three applications were demonstrations on the day of the event; the press release does not say whether, or on what terms, they will be offered to residents afterward, and this site did not attend or try them.

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