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China and the US are wrestling over a web of cables we never see, but rely on every day



We’re all familiar with what our planet looks like. We know the countries, the oceans.

But beneath those oceans is something rarely seen. A technological marvel.

An underwater information superhighway, a global web of nearly 500 cables that lace the contours of the ocean floor.

A web of blue lines form a network over Earth. Australia is visible in the bottom left.

Every viral meme, every email, every Facebook post, every chart-topping hit, every internet site, every online banking transaction … they all rely on this network.

They don’t come through the air. Satellites only provide a fraction of the data you use. Most of it comes through this underwater cable network, the plumbing of the internet itself.

Communications company TeleGeography has mapped these cables, showing how they crisscross the globe, tying countries together.

Those ties begin on a beach, the starting point for everything anyone around the world does, says, or sees online.

This particular one is Narrabeen Beach in Sydney. It’s a beautiful stretch of coastline just over 3 kilometres long, renowned for iconic surf breaks which have been the breeding ground for some of the world’s best surfers.

But it’s also far more than that. It’s a gateway. A number of cables reach out into the ocean from the beach, buried under sand closer to shore to keep them safe.

A network over blue lines are laid over the globe. Labels of nearby Pacific Islands can be seen, along with a "Narrabeen" label.

It’s just one point on Australia’s east and west coasts that are landing points for these cables, which connect to the world via the Pacific.

The Gondwana Cable extends to New Caledonia; the Southern Cross Cable to the US via Fiji and Hawaii; the APNA Cable to Japan, the PPC-1 Cable to Guam and the APNG Cable to Papua New Guinea.

Only a little further south, in Brookvale, is the cable landing station for the JGA South cable, a network that takes us far from the east coast of Australia, up to Guam, where it connects to the JGA North cable and branches to Hong Kong, Japan, and Los Angeles via Hawaii.

These cables aren’t thick. They’re only about the width of a garden hose, and a case of plastic and steel protects glass fibres as thin as a strand of hair that carry the world’s information as tiny pulses of light.

A diagram showing the make-up of an undersea cable.
A diagram showing the make-up of an undersea cable.()

“Most people think they use their phones and things go through the air magically around the world across the continents,” said Alan Mauldin, research director at TeleGeography.

“They don’t. They go under the bottom of the ocean floor.

“So, whenever you use your phone, it’s going from your phone to a cell tower or a Wi-Fi router to a terrestrial cable into a cable under the ocean between Australia and Asia, Asia to Europe to the Americas.”

The network – and the data it contains – is incredibly valuable. It powers almost every aspect of our modern life. But it’s also key for governments, intelligence agencies, and technology giants.

And there’s a worldwide struggle for control, happening under the radar – and under the ocean.

An expanding cloud of smoke is seen highlighted in the ocean. The image is taken from space.

To the east of Australia, mother nature gave Tonga a terrifying experience of life completely cut off from the internet. In December 2021, around 65km north of Tonga’s main island Tongatapu, an underwater volcano began to erupt.

The satellite image shows an expanding cloud of smoke and ash in the middle of the ocean.

Hunga Tonga–Hunga Haʻapai sent plumes of ash into the air, and nearly four weeks later, reached an explosive conclusion.

This satellite image shows the smoke cloud continuing to grow.

On January 15, it erupted with a force “hundreds of times more powerful” than that of Hiroshima’s atomic bomb, sparking tsunamis that swept across the Pacific.

This satellite image shows the ash cloud getting bigger.

Little information about the extent of the damage was known initially because crucially, an undersea cable that connected Tonga to the rest of the world was damaged in the eruption.

The ash cloud has grown in size, looming over the Pacific Ocean in this satellite image.

Ash in the atmosphere also prevented satellite communication.

The ash cloud over the ocean has again grown.

Families overseas were unable to communicate and see if their loved ones were safe, businesses were paralysed, and no-one was able to send any financial assistance back.

The ash cloud from the Tongan volcano has again grown bigger in this satellite image.

“We were totally black. Totally dark from the internet world for about at least three days,” said Tonga Cable’s Semisi Panuve.

It took five weeks for the international cable to be fully repaired. In the meantime, Tongans were forced to rely on makeshift satellite connections as the ash slowly cleared.

It was an example of the vulnerability of this network that is so crucial for everyday life.

But dangers don’t just come from natural disasters.

Like Tongans, the Taiwanese have experience in what it is like to have their connection to the outside world severed.

Myriad cables run through and around Taiwan, a country that nearby China considers a breakaway province that will eventually come under Beijing’s control.

This map image shows myriad cables running between and around China and Taiwan.

It has seen 27 cable breaks in the past five years, which is considered a lot by global standards.

Officially, that’s blamed on Chinese fishing vessels accidentally dragging their anchors on the sea floor and snapping the cables, which take months to repair.

But it has been happening so frequently that authorities in Taiwan have started war-gaming what it would look like to lose their communications with the outside world altogether and what it would mean for domestic security and national defence systems.

“We are no longer the only country that feels Chinese interference in our local politics and democracy,” said Taiwanese policy adviser Enoch Wu.

“We are no longer the country that is subjected to the intellectual property theft that is waged by Chinese actors. We are no longer the only country that faces diplomatic pressure on the world stage … I think all of us are taking this threat a lot more seriously than we used to.”

A new ‘Cold War’

One country, in particular, is taking China very seriously.

This is a new cable that is currently being built by US-owned cable laying company SubCom.

The South East Asia-Middle East-Western Europe 6 — or SE-ME-WE 6 (blue) — will run from Singapore to France, with almost 20,000 kilometres of fibre running along the ocean floor connecting dozens of countries along the way.

This globe has a single long cable highlighted as it weaves between countries.

SubCom is a massive provider — to illustrate this, we’ve highlighted all their cables in blue. 

This map of Earth has a number of cables highlighted blue, while others are greyed out.

They stretch all over the globe and offer the US massive control over the flow of information between countries.

China’s efforts to replicate this are not yet at the same scale.

But Chinese Company HMN Tech (orange) is the fastest growing company in the space. You can use your finger or your mouse to navigate and explore these competing networks.

The globe now has the same cables highlighted blue, but additional ones are highlighted orange.

This map could have looked very different. A Chinese consortium was set to snag the multi-million-dollar SE-ME-WE 6 contract three years ago – a move that would have cemented China’s reputation as the world’s fastest-rising subsea cable builder.

But the US government blocked it, putting pressure on consortium members and snaring the contract through incentives.

It’s just one example of at least six private undersea cable deals in the Asia Pacific region over the last four years where the US has stepped in to keep Chinese companies from winning the contract or forcing a re-routing of cables that would have directly linked China to the US.

A man wearing a black polo shirt speaks while gesturing at the camera.
There’s a clear rivalry between the US and China, says journalist Joe Brock.()

Reuters journalist Joe Brock has written several articles on the cable war being waged between the US and China beneath the waves and described it as “a battle over the plumbing of the global economy”.

“I think what’s happening now is that the geopolitical rivalry between the US and China is so open now. They’re swinging at each other in public, that’s what’s brought these tensions bubbling to the surface,” he said.

“The South China Sea has been essentially blocked off from US companies so they can no longer run cables through there, so they’re running cables around. Chinese companies can’t run cables to the US, which is the biggest internet market in the world.”

China reportedly plans to build its own cable linking Hong Kong to China’s Hainan province, before continuing to Singapore, Pakistan, Saudi Arabia, Egypt and France, a $US500 million project that would give China greater reach and connection in the event they’re blocked again in the future.

But the US is also playing its own game.

Australia is already well served by connections to the Middle East, so the Oman Australia Cable, built in 2021 by SubCom and stretching out from the west coast, was something of a curiosity.

But it’s this detour that’s of interest. It leads to a tiny atoll in the middle of the Indian Ocean.

The globe now only has one cable highlighted, with a label marking "Diego Garcia" to the side.

There’s not much on this lush, tropical island. But there is a US Navy listening station, Diego Garcia – which explains why the US government bankrolled a third of the project.

These cables are an information gold mine, and both the US and China have accused each other of spying on the enormous amounts of data that travel through every minute.

Not only that but both Washington and Beijing are now working on the uncomfortable assumption that cables are susceptible to espionage.

Caught in this struggle between superpowers – described as “the new Cold War between the US and China” – are the smaller countries between.

In May 2023, the Chinese government started talks with 10 nations in the South Pacific, offering loans to help build and expand their communications networks. The provider would be the Chinese technology giant, Huawei.

Huawei has been banned from building communications infrastructure in most Western countries, because of national security concerns that it would be a back door for top secret information to be siphoned off to Beijing – a claim both the company and the Chinese government have denied.

But for many developing countries, the Chinese tech titan is an attractive option, simply because it’s cheaper.

The Chinese government’s charm offensive in the South Pacific has prompted Washington to take action.

The United States is backing a new cable connecting several Pacific Islands, boosting Washington’s influence in the region.

The Central Pacific cable would connect American Samoa with Guam and extend up to 12 Pacific islands, including Samoa and Fiji…

And Papua New Guinea and the Federated States of Micronesia.

The Pacific is at the centre of this globe, with some islands labelled. PNG, Vanuatu and Fiji are some of those.

It’s a tangible sign of the strengthening ties between the US and Pacific Island countries caught in the geostrategic tug-of-war between Washington and Beijing.

“They’re in an incredibly uncomfortable position,” Brock said.

“They’re caught between a rock and a hard place. You look at somewhere like the Pacific islands … where you’ve got countries which are doing deals with China, some countries which are doing deals with the US … all they want is to have the investment in infrastructure like undersea cables.

“Unfortunately, they are caught between the US and China, and they then often have to make a choice.”

A group of workmen bury a cable underneath sand on a beach. A bit further out to sea, a boat is seen.
Tech giants like Facebook are also playing a key role in building cables, like the 2Africa connection.()

The choice isn’t necessarily an easy one.

FBI director Christopher Wray described the Chinese counterintelligence threat as “more deep, more diverse, more vexing, more challenging, more comprehensive and more concerning than any counterintelligence threat than I can think of”.

But former US intelligence contractor Edward Snowden exposed the US using mass metadata surveillance systems for covert access for its intelligence agencies.

“There’s enough evidence for us to know, 10 years ago, Edward Snowden exposed how easy it was for British and American intelligence agencies to hoover up data,” Brock said.

“We know that the US and China have accused each other of extracting data. They haven’t denied that they have those capabilities themselves.”

It may seem like we’re a long way from the tensions between superpowers. Most of us just want to be able to watch videos online or read emails without having to wait too long.

But in an increasingly connected world, the smallest cable connection – or the lack thereof – can have a dramatic effect on the lives of millions.

Watch The Cloud under the Sea on ABC iview.

Submarine cable information supplied by TeleGeography – see a detailed interactive version of the map.


  • Producer: Dan Smith
  • Developer: Ashley Kyd
  • Reporter: Michael Reid
  • Editors: Tim Leslie and Matt Liddy
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