The seabed is becoming a battlefield. The shadow fleet is becoming a weapon.
At Asia's largest defence summit in Singapore, the ministers of three allied nations named the ocean floor as the newest frontier of great-power rivalry. Australia, the United States, and the United Kingdom announced a joint program to develop armed underwater drones capable of guarding the fragile cables that carry nearly all of the world's digital commerce and communication — infrastructure that has been severed at an alarming and historically unprecedented rate. The announcement was less a declaration of victory than an admission: that the arteries of modern civilization are exposed, and that the contest for the deep has already begun.
- Undersea internet cables — carrying 99% of Australia's digital life through just fifteen physical lines — have been cut five times in the Taiwan Strait and three times in the Baltic Sea within eighteen months, at a pace and pattern that defies coincidence.
- Australia's defence minister stood before the region's most powerful military officials and named the seabed a battlefield, warning that shadow fleets operating in the grey zone between commerce and coercion are being used as instruments of state pressure.
- The three Aukus partners announced a new joint program to deploy multi-mission uncrewed underwater vessels armed with sensors and weapons systems, designed to watch, defend, and if necessary act beneath the waves of the Indo-Pacific.
- US Defence Secretary Hegseth invoked Theodore Roosevelt and a record $1.5 trillion defence budget, pressing allies to spend more while warning that no single power would be permitted to dominate the Pacific — yet conspicuously said nothing about Taiwan.
- Australia's decision to purchase three secondhand Virginia-class submarines signals pragmatic urgency over ideal capability, as the undersea domain narrows technologically and the window for establishing deterrence grows shorter.
Richard Marles arrived at Asia's largest defence summit in Singapore with a warning that was almost medieval in its imagery: the seabed, he said, is now a battlefield. He was not speaking in metaphor. Over the past eighteen months, the undersea cables that carry nearly all of Australia's internet traffic — financial systems, health networks, intelligence partnerships — have been severed at a rate without historical precedent. Five cuts in the Taiwan Strait. Three in the Baltic. Whether by accident or design, the pattern demanded a response.
The cables themselves are almost impossibly vulnerable. They cannot move. They cannot defend themselves. A single anchor dropped in darkness can sever a line that carries the digital weight of an entire nation. Marles described them as the arteries of modern civilization — and something has been cutting them open.
The answer announced in Singapore was a new Aukus pillar: a joint program between Australia, the United States, and the United Kingdom to develop advanced uncrewed underwater vessels equipped with sensors and weapons systems. US Defence Secretary Pete Hegseth called them highly adaptable and multi-mission. UK Defence Secretary John Healey promised they would rapidly deliver allied superiority beneath the waves. The drones would watch, sense, and act.
Marles placed the cable threat within a larger pattern he called the shadow fleet — unregistered vessels operating under flags of convenience, moving through the grey zone between commercial shipping and state coercion, serving as vectors for sanctions evasion, illegal fishing, and the energy trade sustaining Russia's war. He directed pointed remarks toward Beijing, calling for greater transparency and warning that existing grey-zone behaviour was inconsistent with a peaceful regional order.
Hegseth's remarks carried their own weight. He invoked Theodore Roosevelt, announced a record $1.5 trillion US defence budget, and warned that no hegemon would be permitted to dominate the Pacific. But he said nothing about Taiwan — a silence that registered loudly in a room full of officials watching for exactly that signal. Arms sales to Taipei have stalled. A Trump-Xi summit this month produced little. The omission, in that context, was itself a statement.
Australia also confirmed it would purchase three secondhand Virginia-class submarines under Aukus — a practical choice that simplified logistics but meant operating older platforms in a theatre where the technological edge is narrowing by the year. The message beneath all the announcements was the same: the deep is contested, the infrastructure is exposed, and the window for establishing deterrence is not as wide as it once seemed.
Richard Marles stood before Asia's largest defence summit in Singapore and delivered a warning that sounded almost medieval: the seabed is a battlefield now. The Australian defence minister was not speaking in metaphor. Over the past eighteen months, undersea internet cables—the physical infrastructure that carries nearly all of Australia's digital life—have been cut at a rate and scale without historical precedent. Five cuts in the Taiwan Strait in that span. Three in the Baltic Sea. Whether accident or design, the pattern is unmistakable, and Marles wanted the room to reckon with it honestly.
The cables themselves are fragile things. They cannot move. They cannot defend themselves. They can be severed by an anchor dropped in darkness. About 99 percent of Australia's internet traffic flows through just fifteen of these cables. Everything depends on them: financial systems, health systems, communications, intelligence partnerships, the basic machinery of a modern state. Marles described them as the arteries of modern civilization, and someone or something has been cutting them open.
The United States, United Kingdom, and Australia responded by announcing a new pillar of their Aukus alliance: a project to develop underwater drone technology designed to protect these cables and maintain military advantage in the maritime domain. US Defence Secretary Pete Hegseth described it as a suite of highly adaptable, multi-mission uncrewed underwater vessels equipped with cutting-edge sensors and weapons systems. UK Defence Secretary John Healey called it a range of advanced battlefield technologies that would rapidly give allied forces superiority beneath the waves. The drones would be deployed to watch, to sense, to act.
Marles framed the problem in broader terms. The cables were only the most visible target of what he called shadow fleets—networks of unregistered vessels operating under flags of convenience, moving through the grey zone between commercial shipping and state coercion. These same ships, he said, were vectors for sanctions evasion, for transporting energy that sustains Russia's war in Europe, for illegal fishing, for human and drug trafficking. The seabed was becoming a weapon. The shadow fleet was becoming a weapon.
He directed much of his speech toward Beijing, calling on China to be more transparent about its maritime operations. He acknowledged that China had an opportunity to contribute to regional stability, but existing patterns of grey-zone activity were inconsistent with a peaceful order. The implication was clear: if these cable cuts were intentional, they represented a test—of response times, of attribution thresholds, of political will. If they were accidents, they still exposed a vulnerability that could not be ignored.
Hegseth's remarks carried their own edge. He said the Trump administration would not let China dominate the Pacific and invoked Theodore Roosevelt's doctrine of speaking softly while carrying a big stick. He announced a record US defence budget request of 1.5 trillion dollars, framed as unleashing America's arsenal of freedom and expanding military dominance for decades. He pressed allies in Europe and Asia to spend more on defence, saying the US wanted partners, not protectorates. A Pacific dominated by any hegemon, he warned, would unravel the regional balance of power.
What Hegseth did not do was mention Taiwan directly. That silence carried weight. Last year, he had warned loudly about the real and potentially imminent threat of Chinese invasion, describing the People's Liberation Army as rehearsing for the real deal. This year, at a summit where Taiwan's future was the issue most keenly watched by officials and ministers from across the region, he said nothing. There is concern in Taiwan that the Trump administration's commitment to the island is less robust than previous US governments. Recent arms sales have stalled. A summit between Trump and Xi Jinping in Beijing this month had been underwhelming. The absence of Taiwan from Hegseth's speech, in that context, was itself a message.
Australia also announced it would purchase three secondhand Virginia-class submarines from the United States under Aukus, rather than a mix of old and new vessels. The decision was framed as simplifying supply chain management, operational requirements, and maximizing cost efficiencies. It was a practical choice, but it also meant Australia would be operating older platforms in a theatre where the technological edge was narrowing. The undersea domain, it seemed, was becoming contested in ways that required constant vigilance and constant upgrade.
Notable Quotes
Over the past 18 months, we have witnessed a series of attacks against subsea critical infrastructure at a scale and frequency that is historically unprecedented.— Richard Marles, Australian Defence Minister
A Pacific dominated by any hegemon would unravel the regional balance of power and undermine the equilibrium we all seek to preserve.— Pete Hegseth, US Defence Secretary
The Hearth Conversation Another angle on the story
When Marles says the seabed is a battlefield, is he describing something that's already happening or warning about what could happen?
Both. The cable cuts are documented—five in the Taiwan Strait, three in the Baltic. But he's also asking a harder question: are these accidents or tests? If they're tests, they're testing how fast we respond, whether we can prove who did it, whether we'll actually do anything about it.
Why does it matter if 99 percent of Australia's internet traffic flows through fifteen cables?
Because it means the entire country is dependent on infrastructure that's exposed and immobile. A single anchor, dropped at night, can sever the connection. There's no redundancy at that scale. It's a vulnerability that can't be moved, can't be hidden, can't be defended except by watching the water around it.
The shadow fleets seem to be doing more than just cutting cables.
Much more. They're moving sanctioned oil to keep Russia's war going. They're moving drugs, trafficking people, enabling illegal fishing. The cables are just the most visible target. The real issue is that these vessels operate in a grey zone where it's hard to prove intent, hard to attribute action, hard to respond without escalating.
Why didn't Hegseth mention Taiwan?
That's the question everyone in Singapore was asking. Last year he was explicit about the threat. This year, silence. It suggests the Trump administration may be signaling something different about its commitment to the island, especially after the underwhelming summit with Xi.
Does buying secondhand submarines undermine Australia's position?
It's a practical choice—simpler logistics, lower cost. But it means Australia is operating older platforms in a theatre where the technological edge matters. It's a trade-off between efficiency now and capability later.