The internet is carried by around 500 fiber-optic undersea cables that are vulnerable to damage from natural disasters and man-made threats.

National actors, such as Russia, China, and the US, have the ability to attack the cables, which could cause massive disruptions to the global internet and weaken transportation grids.

To protect the cables, the US should lead a global effort, including using the United Nations Convention on the Law of the Sea, creating an international military coalition, and incorporating technological advances into the undersea-cable ecosystem.

If you ask the average American, “where does the internet come from?” the answer you would most likely get would be from space, via satellites. Wrong. The vast majority of information that flows across the tens of billions of devices connected to the internet comes from the sea. Around 500 fiber-optic undersea cables carry more than 95% of all internet data, strung like 19th-century telegraph cables under the oceans. And they are very vulnerable.

While the cables are reasonably sturdy — the fiber strands are protected by many layers of copper, steel and plastics — it is possible to damage them. First, they can be vulnerable to natural disasters, both on the floor of the ocean where earthquakes can disturb them, and at the surface where the cables connect to land-based infrastructure.

A second threat is man-made: from terrorists, anarchists, luddites who hate the internet and other random agitators. While such actors can’t really get at the seafloor cables, they can attempt to disrupt the connections at the water’s edge, or use cybertools to hamper the cable operations.

But what really worries geopolitical planners is the ability of national actors — Russia, China, the US, many European powers — to use submarines or surface ships to attack the cables. This can be done as simply as dragging an anchor or a specially designed seafloor tool across the cables, or by having submarines attack them.

Such an operation could cause massive disruptions to the entire global internet, weaken transportation grids, disrupt communications between nations and undermine national and regional defense.

Recognizing this, a bipartisan bill is under consideration in the Senate, co-sponsored by Democrat Jeanne Shaheen of New Hampshire and Republican John Barrasso of Wyoming. Both are noted for reaching across the aisle in matters of national security. The bill reportedly requires a report to Congress in six months, specifically on Chinese and Russian sabotage efforts. It would mandate sanctions on foreign parties responsible for attacks, and have the US provide more resources for protecting and repairing the cables.

That’s a good place to start, but it is hardly sufficient given the scale of potential economic and military disruptions. What should the US do to lead a global effort to keep the internet safe from natural disasters, terrorism and state attacks?

First, use the existing United Nations Convention on the Law of the Sea (UNCLOS) to catalyze international action. (Unfortunately, the US hasn’t ratified the treaty, but generally follows it as a matter of customary international law.) Article 87 of UNCLOS permits the laying of cables on any nation’s continental shelf. It forbids damaging the cables and creates penalties and sanctions against individuals or nations who do so. As with piracy, there are international norms against sabotage, and the International Maritime Organization in London, an organ of the UN, should create a multinational task force for cable protection.

The IMO should focus on incorporating the private sector into the effort, much as it did effectively in the case of Somali pirates more than a decade ago. The huge international industrial, shipping, finance, banking and telecommunications firms all have an enormous stake in a secure and highly functioning internet. Bringing their expertise to bear alongside the global reach of the IMO makes great sense.

A second approach to protecting the cables would be creating an international military coalition. The obvious foundational alliance would be the North Atlantic Treaty Organization. The transatlantic partnership has more than 1,000 major warships, and routinely conducts training exercises and major operations.

Alongside NATO warships, this coalition could include capable Pacific navies — Japan, South Korea, Australia, Singapore — and many other nations might be willing to participate. The NATO-led coalition in Afghanistan included forces from 55 countries. The motivation to protect undersea cables would likely be far higher even than the counterterrorism impetus of the Afghanistan operation.

Finally, there are profound technological advances that could be incorporated into the entire undersea-cable ecosystem. These could be financed by an international consortium of nations, the UN, and through taxes paid by commercial entities, depending on the level of use they make of the internet. Silicon Valley, I’m looking at you.

Some items to consider are using advanced materials for better physical protection of the fiber-optic cables; adding many more backup cables that are kept offline in secret locations and could be brought online when necessary; improving the flow of massive amounts of data to obviate the need for the cables, perhaps through satellite-based systems; and hardening the onshore points of vulnerability with larger security forces and tougher physical barriers.

Finally, the initiative must include significant sanctions or retaliation against any nation, corporation or terrorist group that attacks the cables. Both Russia and China have been accused credibly of doing so — they should be put on notice that this will not be tolerated and that economic penalties will be levied against them. Any offensive actions by national actors should be well-publicized: with photos, videos and documented information.

Protecting the flow of data on undersea cables is crucial to militaries, companies and pretty much every one of us. The Shaheen-Barrasso bill in the Senate is necessary, but far from sufficient. A broader international approach is required.

Bloomberg, 26 November 2025… by James Stavridis