Australia’s submarine cables are privately owned and operated, and commercial repair operators handle maintenance and repair under contract (Getty Images)

Australia all at sea on submarine cable risks

Aging fleets and a leadership void threaten the country's subsea cable resilience.

Jocelinn Kang

12 December 20254 min read

Google is laying new submarine cables along Australia’s northern and western approaches. The routes will link to a planned Google AI data centre on Christmas Island, likely building on an existing cloud deal with the Australian Department of Defence. The cables also connect to naval base HMAS Stirling, 35 kilometres south-west of Perth, which will host AUKUS partners and nuclear-powered submarines. Together, these moves reflect a shift in Defence planning as senior officials warn that the regional security environment is worsening.

Australia’s Chief of Navy Mark Hammond described seabed cables at an address last month as “our lifelines”, noting that their loss would pose “an existential threat to our island and to our people”. His assessment reflects a growing recognition that the integrity of these cables underpins Australia’s economy, military networks and connections to the world.

Yet no agency seems responsible for protecting these digital lifelines in a crisis. Defence, Maritime Border Command and Home Affairs all have adjacent interests, but none has the mandate to lead.

Nor does the government have a mechanism to task a repair ship if a cable were cut. Until now, it has not needed to. Australia’s submarine cables are privately owned and operated, and commercial repair operators handle maintenance and repair under contract. In peacetime, this works well enough. There’s enough network redundancy to absorb delays when faults occur. But as security conditions deteriorate, the question becomes whether those peacetime arrangements remain fit for a world where these cables are also a national security consideration.

The government has decided to create a maritime strategic fleet to move critical cargo in a crisis and to support maritime workforce capability, but there has been no call on undersea cable repair.

Meanwhile, the commercial repair sector is under strain. Specialised cable vessels and their equally specialist crews are ageing faster than they are being replaced. Around 64 per cent of the global repair fleet will reach the end of its 40-year service life by 2040. Investment in vessels is sporadic due to high capital costs, uncertain demand and maintenance economics that reward operators more for laying cables than repairing them. Crew replenishment is also uncertain because the skills are learned on the job, not through any formal pipeline.

A new repair ship can cost more than US$100 million and take several years to deliver. For investors, that is a risk if future demand remains opaque.

A new repair ship can cost more than US$100 million and take several years to deliver. For investors, that is a risk if future demand remains opaque. To add to this, paradoxically, fault numbers have not increased despite cable growth. It’s suggested that this is because of improved installation methods and engaging third parties to monitor and alert ship traffic near their cables. As a result, the economic case for new repair capacity weakens.

This is where the real problem lies. The inefficiencies in fleet use and maintenance contracts could be viewed as market failures for industry to solve. But they may also be strategic vulnerabilities that demand government intervention. The answer is blurred because national security interests now intersect with infrastructure long treated as a private service.

Other nations have reached or are working on their own conclusions. A UK parliamentary inquiry recommended a national repair ship and Royal Navy crews trained for cable repair. France bought back control of powerhouse submarine cable company Alcatel Submarine Networks, which can manufacture, lay and repair cables. India is exploring whether to build its own repair ships or convert navy ships for the task. The United States, by contrast, has moved the other way by defunding its Cable Security Fleet.

In Australia, the issue remains unaddressed.

If the government does choose to act — by building workforce capability, brokering allied access, funding a vessel or reducing investment risk — delivery would take years. That is why clarity matters now. The line between government and industry responsibility is undefined. No department owns the problem. Until that changes, Australia will keep relying on market forces and peacetime systems.

Acting now carries no downside. Even without conflict, increased repair capability would lift digital resilience and support national priorities, including artificial intelligence.

Waiting until a crisis is too late.

This article was written as part of a multi-year project being undertaken on Defending Seabed Critical Infrastructure by the Australia India Institute, University of Melbourne, with the support of the Australian Department of Defence. View expressed are solely those of the author.

About the author

Jocelinn Kang

Jocelinn Kang is a strategist and technology communicator with more than 20 years' experience in cybersecurity in the national security domain.

Topics

Australia Defence & security AUKUS Intelligence & security Cyber & technology