Subsea cables are emerging as the new underwater battleground — these are the island nations most at risk from attacks

• Report finds five island nations depend entirely on one vulnerable underwater internet cable
• Accidental ship anchoring causes most global undersea cable failures every year
• Smaller island nations remain dangerously exposed to complete nationwide internet blackouts

A new report has highlighted how all 48 island nations worldwide, including major economies such as the United Kingdom, Japan, and Indonesia, rely on just 126 undersea cables for their internet connectivity.

These cables are often no thicker than a garden hose, making them surprisingly vulnerable to accidental damage or deliberate sabotage.

The International Cable Protection Committee reports 150 to 200 faults on undersea cables each year, with 70 to 80% resulting from accidental human activities like anchoring, while the others stem from technical failures, natural disasters, or suspected malicious actions that are difficult to prove.

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Which island nations face the highest risk of being cut off?

To determine the level of vulnerability of these island nations, Comparitech analyzed three factors, including the number of cable connections, fishing activity levels, and proximity to active armed conflicts.

The study attributed scores ranging from 0, which represents the least risk, up to 8, which represents the most severe exposure.

New Zealand scored 0 due to having more than 10 different cables, no engagement in armed conflict, and relatively modest industrial fishing activity.

Iceland emerged as the most at-risk European nation with an overall score of 5. Brunei and Bahrain each scored 6, making them the most vulnerable Asian island nations in the study.

Five of the smaller, less populated island nations are connected by just a single undersea cable with no backup option available.

Tuvalu relies on the 668-kilometer VAKA cable, which is merely a spur off a larger regional system.

Nauru's initial connection feeds into the 2,250 kilometer East Micronesia Cable System, which must link into other networks to reach Guam.

Kiribati depends heavily on a spur of the 13,700-kilometer Southern Cross NEXT cable for all of its connectivity needs.

All nations with a single cable are highly at risk because any disruption to that cable means total blackout for the entire country.

For example, in 2022, Tonga lost internet access nationwide for over five weeks after an undersea volcano severed its only cable connection.

Geopolitical tensions are making the ocean floor a new battlefield

The growing geopolitical sensitivity around subsea cables, alongside reported reconnaissance show how these systems are increasingly viewed as strategic military assets.

Iran's Islamic Revolutionary Guard Corps recently revealed it had mapped cable locations throughout the Strait of Hormuz, placing regional digital infrastructure at significant risk.

The UK military has tracked Russian submarines performing reconnaissance on cables in the North Atlantic Ocean.

China has successfully tested a cable cutting device that works at depths of up to 4,000 meters using advanced manned and unmanned submersibles.

The vulnerability of island nations to undersea cable disruption is less a question of if outages will occur and more a question of when and how severely they will be felt.

Connectivity is highly concentrated, and in some cases dependent on single systems or indirect spur branches that offer no redundancy when trouble strikes.

While major economies like the United Kingdom or Japan benefit from extensive redundancy and multiple landing points, smaller and more remote nations remain structurally exposed to complete isolation.

This exposure is compounded by the difficulty of monitoring and protecting infrastructure that spans thousands of kilometers of ocean floor.

Repair fleets have only four dedicated ships worldwide, while cable ownership concentrates among a few operators, making new systems too costly for small nations.

Until smaller nations gain alternative connections or dedicated repair vessels, they stay one broken cable from digital darkness, a vulnerability adversaries are already mapping.

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