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Sixteen privately owned subsea cables carrying 99 percent of Australia’s internet traffic are a …
The Invisible Vulnerability Beneath the Ocean Floor
For an island continent like Australia, international data dependency is absolute. According to the ANU National Security College paper, 16 privately owned subsea cables handle 99 per cent of the nation’s inbound and outbound internet traffic.
Global threats to this infrastructure are no longer theoretical. In Europe, Russian-associated freighters have repeatedly severed communication lines by deliberately dragging their anchors across the ocean floor. The Australian Defence Force is tracking these exact scenarios. Air Commodore Paul Pettigrew, Joint Force Cyber Component Commander, addressed the reality of the threat at the 2025 Military Communications and Information Systems (MiLCIS) conference in Canberra.
“All I can say is we are tracking; we are understanding that. We understand implicitly the communication lines throughout our theatre,” Air Commodore Pettigrew stated at the conference, noting that his team visualizes commercial ships dragging their anchors over critical routing paths. “We’re turning our mind to what the threats are to that and what effectors could impact that physically… and also logically through cyber space.”
Operationalizing the Cyber Warfighting Domain
Physical cable cuts are only half the battle.
Chief of Joint Operations Lieutenant General Susan Coyle outlined the structural shift during her address at MiLCIS. She noted that the cyber warfighting domain is fully operational, contested 24/7, and continuously evolving in its character.
“We are not just a support function or an enabler. It is the generation and employment of cyber power and it is a strategic capability that has to underpin integrated operations, to shape the battlespace and defence and protect our national interests,” Lieutenant General Coyle said. She added that cyber operations are now fully integrated across strategic, operational, and tactical levels.
Tactical cyber missions assure military communications and enhance survivability, while strategic operations support deterrence and national resilience. Yet, securing military links does little to insulate civilian infrastructure from widespread outages if underlying commercial pathways fail.
What Happens When the Pipes Break
Rear Admiral Andrew Quinn, head of space and cyber capabilities in the Joint Capabilities Group, emphasized the need for open dialogue to recognize subsea cables as vital national infrastructure.
“Defence has some discrete capabilities that we can do to assure capability, that the rest of the general population does not have, as you would expect,” Rear Admiral Quinn acknowledged at MiLCIS. “But the impact of starting to knock cables off will be a huge impact on the Australian community. I would expect banking would really struggle very, very, quickly.”
The 30-Second Verdict
- The Asset: 16 privately owned subsea cables carrying 99% of Australia’s internet traffic.
- The Threat: Physical sabotage via anchor dragging, mirrored by real-world incidents in Europe, alongside logical cyberattacks.
- The Defense: The ADF is actively integrating cyber and physical protection strategies, though civilian sectors like banking remain intensely vulnerable to rapid disruptions.
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