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Opinion: Strategic analyst Shay Gal warns Australia’s economic, security and social lifelines depend on fragile undersea internet cables that are vulnerable to accident and exploitation, demanding urgent updates to regulation, diversification and seabed defence.
Beneath the Southern Ocean lies Australia’s most fragile centre of gravity. The nation’s trade, banking, aviation, logistics, intelligence sharing and daily life depend not on satellites but on hair-thin glass threads across the seabed.
Industry and government sources put the figure at well over 95 per cent of international traffic – the Australian Strategic Policy Institute has written that for Australia, it is closer to 99. In deep water, those cables are no thicker than a garden hose.
Australia’s sovereignty no longer ends at the shoreline; it extends down the continental slope, to the glass arteries of the nation’s digital heart.
Canberra has not been blind to this vulnerability. Since 2007, it has operated a world-class legal regime under Schedule 3A of the Telecommunications Act, empowering the Australian Communications and Media Authority to declare protection zones that prohibit anchoring, trawling and seabed works around landing routes.
Northern Sydney, Southern Sydney and Perth have been covered, with restrictions stretching out to 2,000 metres’ depth. Yet the map of cables has multiplied and shifted while the zones have remained static.
Only now is the regulator consulting on expanding the Southern Sydney zone to cover new landings, including Google’s planned routes near Maroubra. It is a welcome step, but it underlines how much our rules must catch up to the digital reality they are meant to protect.
Most cable cuts are accidents – anchors dragging, trawl nets scraping. But in the grey zone, negligence becomes camouflage. Finnish prosecutors have charged the captain and officers of the Eagle S tanker after a 90-kilometre anchor run allegedly severed multiple links in the Baltic.
Around Taiwan’s Matsu Islands, repeated breaks have forced emergency reroutes. In the Red Sea, outages in 2024 slowed Asia–Europe traffic while war raged above.
For Australia, this is not hypothetical. Former senior officials warned that the first move in a major crisis would be to choke undersea connectivity – causing economic shock, public anxiety and command friction before a single shot is fired. The same cut that ruins a family video call can stall commodity trading, ground aircraft, hobble emergency services and disrupt allied coordination.
That is why the voyage of the Chinese research vessel Tan Suo Yi Hao mattered. Officially returning from joint science in New Zealand, in reality, it carried the Fendouzhe submersible and sensors able to map and service seabed devices. Operating near cable corridors while remaining within the law of the sea, it embodied the ambiguity of modern competition: lawful in form, strategic in effect.
The prime minister’s words were blunt – he would “prefer that it wasn’t there” – as agencies tracked its course and experts noted its ability to collect militarily relevant bathymetry and acoustic data. For Beijing, science at sea is a strategy by other means. The lesson is not to panic at every hull on AIS. It is to understand that science and power have fused below the thermocline, and that posture, not protest, is what counts.
Posture begins with awareness. Protection zones are necessary but no longer sufficient. In an age of uncrewed vehicles and long-endurance motherships for seabed operations, the shield must move from the surf line to the shelf and beyond.
The government’s decision to engage AUKUS Pillar II on subsea and seabed warfare and to field sovereign large autonomous underwater vehicles such as Ghost Shark is the right pivot: a persistent covert presence along cable corridors, combining acoustic and non-acoustic sensing with the ability to inspect, deter and, if required, interdict. This is not about picking a fight. It is about injecting friction into hostile action and giving confidence back to markets and citizens.
Resilience is not just about defending cables – it is about designing them differently.
They must not bunch into a handful of postcodes. Routes and landings should be engineered for separation and depth, with easy repair access. Restoration must be rehearsed and guaranteed.
Here, Australia can lead. The Cable Connectivity and Resilience Centre, our Quad contribution, is a vehicle for shaping regional norms: helping Indo-Pacific neighbours plan diverse routes, share incident data and build legal frameworks so a break in one exclusive economic zone does not cascade across many.
What we codify at home –- updated protection instruments, mandatory incident reporting, real-time monitoring – will carry double weight if we help others do the same.
Deterrence in the grey zone rests as much on attribution as on presence. Europe’s experience shows that rigorous investigation, AIS data, seabed surveys and a readiness to press charges – even outside territorial seas – can raise the cost of “accidental” anchor drags.
Australia should signal now that in our waters and zones, we will investigate, publish and, where evidence leads, prosecute. That we will fuse maritime domain awareness with seabed awareness.
That spare parts, repair ships and pre-arranged charters are funded as seriously as frigates. The internet’s backbone is steel and glass. Its defence must be as real as the material.
This is a once-in-a-generation statecraft task.
It is neither a call for panic nor for militarising science. It is a call for disciplined leadership: to update regulation with the urgency we update fleets; to diversify routes and rehearse restoration; to deploy quiet technologies that guard the seabed without fanfare; and to turn Australia’s strengths – engineering, alliances, geography – into a credible guarantee that the nation’s digital lifeline will endure.
The cables will remain unseen by most Australians. The work to secure them must not be.
Shay Gal is a strategic analyst and adviser specialising in international security, diplomatic strategy and geopolitical crisis management. He advises senior government and defence leaders on complex strategic challenges.
