Could Drones Make Submarines Obsolete?

Key Points – Despite recurring claims of their obsolescence due to advancements in drones and surveillance, submarines, particularly nuclear-powered ones, remain more critical than ever for national security.

-Unmanned underwater vehicles (UUVs) – or drones –  are tactical tools with limited range, autonomy, and payload, lacking the submarine’s unique ability to project strategic power through stealth, endurance, and ambiguity.

-Submarines can cross oceans undetected, linger off hostile shores, launch significant payloads, and deploy special forces. Crucially, only submarines possess the capability to persistently monitor and protect vital, vulnerable undersea infrastructure like fiber-optic cables, a domain increasingly eyed by potential adversaries like Russia and China.

Drones Won’t Replace Submarines?

Every few years, a new wave of defense analysts and tech enthusiasts gathers to pronounce the submarine obsolete. They point to developments in drone swarms, acoustic networks, and satellite surveillance. They argue that oceans are becoming “transparent,” that stealth is no longer possible, and that the undersea domain has finally been cracked open by a revolution in sensors and AI. In this telling, the submarine is yesterday’s weapon – a Cold War relic too large, too expensive, and too easy to find.

But the submarine isn’t dead. It’s more relevant now than it has been in decades. And no, drones can’t replace it – no matter how many breathless tech briefings try to claim otherwise.

Let’s dispense with the fantasy. Drones – unmanned underwater vehicles, or UUVs – have their uses. They can scout terrain, hunt mines, relay signals, and even drop sensors in carefully defined mission sets. But they’re tactical tools. They don’t project power. They don’t deter. They don’t carry serious payloads, and they don’t survive long without human oversight. In real-world conditions—contested waters, no guarantee of comms, no margin for error—they’re limited. Useful, but narrow. They assist. They don’t lead.

A submarine, by contrast, leads. And it does so by disappearing.

Nuclear-powered submarines can cross oceans undetected. They can linger off hostile shores for weeks. They can track enemy vessels, launch cruise missiles, or deliver special forces – all without being seen, let alone countered. No other platform offers this combination of endurance, flexibility, and survivability. UUVs don’t come close. Their range is short. Their autonomy is partial. Their missions are constrained. And once a drone is found, it’s vulnerable. It has no means of escape, no defenses, and – critically – no ambiguity.

Strategic ambiguity is the heart of submarine power. An adversary doesn’t need to know where your submarine is – only that it might be nearby. That possibility imposes costs. It forces caution. It complicates planning. It introduces the kind of uncertainty that good strategy thrives on. A drone, once detected, removes uncertainty. It’s either present or not. It either functions or it doesn’t. It can’t loom, shadow, or haunt. It can’t impose silence.

Nor can a drone project strategic power. Drones cannot launch a salvo of Tomahawks into an adversary’s missile site. They cannot deploy a SEAL team onto a hostile beachhead. They cannot shadow a rival’s ballistic missile submarine while remaining undetected. They cannot conduct real-time intelligence-gathering in contested areas, integrate with strike networks, and deliver kinetic effects in a single mission. Submarines can – and do. They are not just assets. They are sovereign instruments, shaped by purpose and driven by consequence.

And they are only becoming more vital.

Consider the undersea cables. More than 95% of global internet traffic, financial transfers, and sensitive government communications move through a thin web of fiber-optic lines buried on the ocean floor. These cables are poorly defended and barely acknowledged in public, but they are critical to everything from Wall Street trading to NATO operations. In the event of great power conflict, they will be high-value targets—easy to cut, hard to attribute.

Russia and China already understand this. Moscow’s GUGI submarines have mapped undersea cable routes throughout the North Atlantic. Chinese oceanographic vessels are doing the same in the Pacific and Indian Oceans. These aren’t scientific surveys. They’re battle preparation. They’re probing our nervous system for weaknesses. And if those cables are sabotaged in a future conflict, the world won’t go dark because of a drone. It’ll go dark because a submarine—ours or theirs—got there first.

Only a submarine can operate long enough, quietly enough, and deeply enough to patrol this domain. Only a submarine can loiter near cable junctions without being seen. Only a submarine can investigate and, if necessary, counter hostile activity near seabed infrastructure. And if a submarine is conducting those operations, you’ll probably never know until the cable goes out.

This is the environment into which Canada is now belatedly considering sending its own submarine fleet. After years of strategic sleepwalking, Ottawa has announced plans to procure up to twelve conventionally powered submarines. That’s a good start—but it will only matter if the fleet is funded, built, and deployed with a clear sense of purpose.

Predictably, critics are already lining up to call it wasteful. Why not just use drones, they ask. Why not buy more satellites? Why not invest in climate monitoring or cyber defense instead?

Because drones can’t do what submarines can do. Satellites can’t stop a foreign adversary from cutting a cable under the Arctic ice. Cyber defense is meaningless if your physical infrastructure has been severed. And climate resilience doesn’t matter much if you can’t even defend your own maritime approaches.

Canada needs submarines not for vanity or prestige, but for survival as a serious actor in the world’s most contested waters. The Arctic, the North Atlantic, and the North Pacific are rapidly becoming frontiers of confrontation. Russian and Chinese naval movements are increasing. U.S. expectations are growing. If Canada wants to assert sovereignty, contribute to deterrence, and avoid being bypassed altogether, it needs the ability to patrol the depths on its own terms.

The Americans understand this. The British understand it. The Australians, through AUKUS, are rebuilding their entire defense posture around submarines. The French continue to maintain a formidable undersea force. And Beijing is quietly expanding one of the most ambitious submarine programs in the world. They are all preparing for the next strategic frontier. And that frontier is underwater.

In this context, the drone fixation looks less like innovation and more like avoidance—a way of pretending that hard choices about hard power can be sidestepped with clever tech. But war is not a software update. Strategy is not an app. It’s a human contest, fought in friction and uncertainty. And the submarine is one of the few platforms still capable of thriving in that environment.

Drones vs. Submarines: No Contest

Let drones scout and assist. Let them map terrain and sniff for mines. But do not pretend they can replace the submarine. They cannot.

The next war won’t be announced on Twitter. It may begin with a broken cable, a missing ship, or the silence of a satellite feed gone cold. When that day comes, it won’t be a drone that provides answers. It will be a submarine. Silent. Waiting. Watching. Acting.

About the Author: Dr. Andrew Latham

Andrew Latham is a non-resident fellow at Defense Priorities and a professor of international relations and political theory at Macalester College in Saint Paul, MN. You can follow him on X: @aakatham.

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