Undersea Cable Damage Log: Baltic Sea, Taiwan, Red Sea and Australia Incidents Since 2023
Subsea cables carry almost all international internet traffic, and they break often. The industry records roughly 150 to 200 faults a year, most caused by fishing gear and ship anchors in shallow water. Since 2023 a cluster of breaks near geopolitical flashpoints has drawn much closer attention. This log records the significant incidents in date order, with the suspected vessel, what investigators found and where each case stands.
Last updated: 15 September 2026.
How to read this log
Suspicion is not attribution. In most cases below a vessel was identified near the damage, often with its anchor down. Proving that a crew acted deliberately, let alone on state orders, has been very hard. Several cases ended with courts or prosecutors finding the damage accidental or the evidence insufficient. The log notes outcomes where they are public.
2023
February 2023: Matsu Islands, Taiwan
The two main cables linking Taiwan to the Matsu Islands (TPKM-2 and TPKM-3) were cut within days of each other. Taiwanese authorities linked the damage to a Chinese fishing vessel and a Chinese cargo ship. About 13,000 residents lost normal internet access for around 50 days, relying on a slow microwave backup until repair ships arrived. Officials said there was no evidence of deliberate tampering by Beijing.
7–8 October 2023: Balticconnector, Gulf of Finland
The Balticconnector gas pipeline between Finland and Estonia was severed, and telecom cables linking Estonia with Finland and Sweden were damaged in the same period. Finnish investigators found the Hong Kong-flagged container ship NewNew Polar Bear had dragged its anchor across the seabed. Its captain later appeared in court in Hong Kong on criminal damage charges.
2024
February 2024: Red Sea
Three major systems, AAE-1, Seacom and EIG, were damaged in the southern Red Sea. The leading explanation is the anchor of the Rubymar, a cargo ship hit by a Houthi missile that drifted for days before sinking. Repairs were delayed by the security situation. Traffic between Asia, Europe and East Africa was rerouted.
17–18 November 2024: BCS East-West Interlink and C-Lion1, Baltic Sea
Two cables were cut within about a day. BCS East-West Interlink links Lithuania with Sweden’s Gotland, and C-Lion1 links Finland with Germany. The Chinese bulk carrier Yi Peng 3 was tracked over both locations. Investigators from Germany, Sweden, Finland and Denmark were allowed aboard alongside Chinese officials. A Swedish inquiry found no conclusive evidence of wrongdoing.
25 December 2024: Estlink 2, Gulf of Finland
The Estlink 2 power cable between Finland and Estonia failed along with four telecom cables. Finland seized the Cook Islands-registered tanker Eagle S, which it described as part of the shadow fleet carrying Russian oil around sanctions. Investigators found anchor drag marks on the seabed. In October 2025 a Finnish court dismissed the case against the captain and senior officers.
2025
3 January 2025: Trans-Pacific Express cable, northern Taiwan
A branch of the Trans-Pacific Express cable north of Keelung was damaged. Suspicion fell on the Shunxing-39, a cargo ship owned by a Hong Kong-registered company and sailing under a flag of convenience. Traffic moved to other cables without major disruption.
26 January 2025: Latvia–Gotland cable
A fibre-optic cable between Latvia and Gotland stopped working. Sweden boarded the Maltese-flagged bulk carrier Vezhen, whose operator said its anchor had dropped in high winds. A Swedish prosecutor ruled the damage accidental and released the ship.
25 February 2025: Taiwan–Penghu No. 3 cable
The cable linking Taiwan to the Penghu Islands was severed about 14.7 km off Tainan. Taiwan’s coast guard detained the Togolese-flagged Hong Tai 58, which had a Chinese crew and Chinese funding and had been anchored near the cable. The captain was charged in April 2025, the first such prosecution in Taiwan, and was later sentenced to three years in prison.
6 September 2025: Red Sea, near Jeddah
The SEA-ME-WE 4, IMEWE and FALCON GCX systems were cut near Jeddah, Saudi Arabia. Internet speeds slowed in India, Pakistan, Saudi Arabia, the UAE and Kuwait, and Microsoft warned of higher latency on Azure traffic through the Middle East. Industry analysis pointed to a commercial ship dragging its anchor. Houthi involvement was suspected by some but not established.
30–31 December 2025: Gulf of Finland
Elisa’s Helsinki–Tallinn telecom cable was damaged on 31 December, and Arelion reported damage to another Finland–Estonia cable the same day, with an Estonia–Sweden link failing on 30 December. Finnish special forces boarded the cargo ship Fitburg, sailing from Russia under the flag of St Vincent and the Grenadines, and found its anchor in the water. In March 2026 Finland’s National Bureau of Investigation confirmed the ship had dragged its anchor across the Elisa cable over tens of kilometres.
2026
2 January 2026: Lithuania–Latvia cable
An Arelion cable between Šventoji in Lithuania and Liepāja in Latvia was damaged a few kilometres from its landing station. Latvian police boarded a ship in Liepāja but said days later they had found no evidence linking it to the break.
30 March 2026: Taiwan–Matsu No. 3 cable
Optical fibres in the Dongyin–Beigan section were damaged while the Chinese salvage vessel Hai Hong Gong 66 worked to remove a stranded Chinese fishing boat. The coast guard detained 11 crew and took the captain ashore for questioning, and the case went to prosecutors.
Late April 2026: Taiwan–Matsu No. 3 cable, again
The same section broke fully after bad weather apparently shifted the fishing boat wreck onto the cable. Taiwan switched Dongyin’s roughly 1,500 residents to microwave backup and scheduled repairs for the end of July. Matsu’s cables have been cut more than 20 times in five years.
9–10 August 2026: Indigo West and Indigo Central, off Perth
Two SUBCO cables carrying traffic between Australia and Southeast Asia failed in quick succession inside the Submarine Cable Protection Zone off Perth. A UAE-managed product tanker had been sailing a racetrack pattern over the charted cable area at the time. SUBCO asked the Australian Federal Police to investigate. Authorities cited suspicious vessel activity but have not named or charged anyone.
Summary table
| Date | Location | Cable or asset | Vessel of interest | Outcome |
|---|---|---|---|---|
| Feb 2023 | Matsu, Taiwan | TPKM-2, TPKM-3 | Chinese fishing vessel and cargo ship | No evidence of deliberate act announced |
| Oct 2023 | Gulf of Finland | Balticconnector, telecom cables | NewNew Polar Bear | Captain charged in Hong Kong |
| Feb 2024 | Red Sea | AAE-1, Seacom, EIG | Rubymar (drifting after missile strike) | Anchor drag widely accepted |
| Nov 2024 | Baltic Sea | BCS East-West, C-Lion1 | Yi Peng 3 | No conclusive evidence |
| Dec 2024 | Gulf of Finland | Estlink 2, four telecom cables | Eagle S | Case dismissed Oct 2025 |
| Jan 2025 | Northern Taiwan | Trans-Pacific Express | Shunxing-39 | Under investigation |
| Jan 2025 | Baltic Sea | Latvia–Gotland | Vezhen | Ruled accidental |
| Feb 2025 | Taiwan Strait | Taiwan–Penghu No. 3 | Hong Tai 58 | Captain convicted |
| Sep 2025 | Red Sea | SMW4, IMEWE, FALCON GCX | Unnamed commercial ship | Anchor drag suspected |
| Dec 2025 | Gulf of Finland | Elisa and Arelion cables | Fitburg | Anchor drag confirmed Mar 2026 |
| Jan 2026 | Baltic Sea | Lithuania–Latvia | Ship boarded in Liepāja | No link found |
| Mar 2026 | Matsu, Taiwan | Taiwan–Matsu No. 3 | Hai Hong Gong 66 | Referred to prosecutors |
| Apr 2026 | Matsu, Taiwan | Taiwan–Matsu No. 3 | Wreck moved by weather | Repair scheduled |
| Aug 2026 | Off Perth | Indigo West, Indigo Central | UAE-managed tanker | Police asked to investigate |
Patterns
The incidents cluster in shallow, busy waters. The Baltic Sea averages around 55 metres deep and the Taiwan Strait around 150 metres, well within reach of a dragged anchor. Many of the vessels involved were Chinese- or Russian-linked, often with flags of convenience or opaque ownership.
The official view has shifted over time. By mid-2026 officials in several North Sea and Baltic governments had grown more confident that most recent breaks were accidents rather than directed sabotage. Investigators still keep running into the same problem: on a tracking feed, an accidental anchor drop and a deliberate drag look identical.
Policy response
NATO launched Baltic Sentry in January 2025 to patrol the region with ships, aircraft and naval drones. The EU adopted an Action Plan on Cable Security in February 2025 and followed with a €347 million subsea infrastructure package in February 2026. Taiwan has moved to classify its cables as critical infrastructure and has tested low-orbit satellite links for its outlying islands. The UK brought in legislation with new penalties for reckless cable damage in 2026.
Repair capacity remains the weak point. Only a small fleet of specialised cable ships exists worldwide, and a single repair can take weeks to schedule.