Australia's Pacific communications would collapse in a Taiwan crisis. Here's why.
China's new deep-sea cable-cutting technology can sever the undersea lines carrying 99% of Australia's data to Pacific partners. Satellites cannot compensate. HF radio offers only degraded backup. The honest assessment is sobering.
🎧 Listen to this article
The Fragile Thread
Ninety-nine percent of Australia’s international data flows through cables thinner than a garden hose. In a Taiwan crisis, China could sever them in hours.
The scenario is not hypothetical. In March 2025, China unveiled a deep-sea cable-cutting device capable of slicing through armored telecommunications lines at depths of 4,000 meters. The machine—a titanium-chassis cutter with a diamond-coated grinding wheel spinning at 1,600 rpm—represents the industrialization of a capability that was once theoretical. According to the South China Morning Post, the device could “reset world order” by targeting the undersea nervous system that connects continents.
For Australia, this is not an abstract geopolitical concern. It is an operational vulnerability with a specific geographic expression. The Southern Cross Cable Network, the Australia-Japan Cable, and the Coral Sea Cable System all traverse waters where Chinese naval assets operate with increasing frequency. The Pacific islands that Australia counts as strategic partners—Papua New Guinea, Fiji, the Solomon Islands, Vanuatu—depend on the same fragile infrastructure. When those cables go dark, so does Australia’s ability to coordinate with the very nations it has pledged to defend.
The question is not whether Australia can maintain some communications with its Pacific partners during a crisis. It can. The question is whether those communications can carry the volume, security, and reliability that modern military coordination and civilian governance require. The answer, examined closely, is troubling.
The Architecture of Exposure
Australia’s Pacific communications rest on a hub-and-spoke topology that concentrates risk rather than distributing it. Sydney serves as the primary landing point for most international cables. From there, traffic routes through a handful of chokepoints—Guam, Fiji, Papua New Guinea—before dispersing to smaller island nations. This architecture optimizes for peacetime efficiency. It is catastrophically unsuited to wartime resilience.
Consider the arithmetic. TeleGeography’s 2024 Submarine Cable Map identifies 559 active or under-construction cable systems globally, with 1,636 landing points. Australia connects to this network through perhaps a dozen primary cables. The Southern Cross system alone carries a substantial share of trans-Pacific traffic. Sever three or four cables in the right locations, and Australia’s digital connection to its northern neighbors degrades from broadband to dial-up—or worse.
The Pacific islands face even starker exposure. Many rely on a single cable for international connectivity. The Coral Sea Cable System, completed in 2020 to connect Papua New Guinea and the Solomon Islands to Sydney, was explicitly designed to reduce these nations’ dependence on cables routed through other countries. It succeeded—but in doing so, it created a new single point of failure. The cable that was meant to secure connectivity now represents a concentrated target.
China understands this geometry intimately. As Trends Research has documented, Beijing has pursued a deliberate strategy of expanding its undersea cable footprint while developing capabilities to disrupt competitors’ networks. The cable-cutting device is merely the most visible manifestation of a broader approach that includes cable-laying ships, deep-sea survey vessels, and the technical expertise to operate them.
The legal framework offers little protection. UNCLOS Article 113 requires states to criminalize intentional cable damage, but enforcement depends on flag-state jurisdiction. If a Chinese-flagged vessel cuts a cable in international waters, prosecution depends on Beijing’s cooperation. This is not a gap in the law. It is the law functioning as designed—for a world where major powers respected mutual restraint.
Satellites Cannot Save You
The instinctive response to cable vulnerability is satellite redundancy. If cables fail, satellites will carry the load. This assumption pervades much Australian defense planning. It is dangerously optimistic.
Australia’s military satellite communications currently depend on a narrow set of assets. The SES IS-22 satellite provides ultra-high frequency connectivity for the Australian Defence Force. Access to the American Wideband Global Satcom (WGS) system offers additional capacity. But these systems were designed for peacetime operations with wartime surge capacity—not for replacing an entire terrestrial communications infrastructure while simultaneously supporting combat operations across a contested theater.
The numbers expose the fantasy. Submarine cables carry terabits per second. Military satellite systems carry megabits. The gap is not incremental; it is categorical. In a crisis where cables are severed, Australia’s satellite capacity would face simultaneous demands from military command and control, intelligence sharing with allies, coordination with Pacific partners, and—critically—the civilian communications that enable those partners’ governments to function. Something would have to give. Probably everything.
Commercial low-Earth orbit constellations like Starlink offer theoretical alternatives. Their distributed architecture resists single-point failures. Their capacity continues to expand. But dependence on commercial LEO systems introduces its own vulnerabilities. These are American companies, subject to American export controls and American strategic priorities. In a Taiwan crisis, Washington might redirect constellation capacity to support its own operations. Australia would join the queue.
There is also the jamming problem. As CSIS has documented, satellite signals can be disrupted through electronic warfare. China has invested heavily in anti-satellite capabilities, including ground-based jammers that can degrade or deny satellite communications across wide areas. The same crisis that severs cables would likely see aggressive jamming of satellite alternatives. Australia’s 2024 National Defence Strategy acknowledged this reality, allocating $9-12 billion for enhanced space capabilities and shifting from single-orbit to multi-orbit approaches. But capability development takes years. A Taiwan crisis could come in months.
The HF Fallback and Its Limits
When satellites fail and cables are cut, high-frequency radio remains. It is the technology of last resort—and it shows.
HF radio works by bouncing signals off the ionosphere, enabling beyond-line-of-sight communication without satellites or cables. It is resilient, distributed, and nearly impossible to completely suppress. It is also slow, unreliable, and bandwidth-starved. The ionosphere is not a mirror; it is a turbulent medium that distorts, delays, and sometimes swallows signals entirely. Operators speak of “skip zones”—regions where signals cannot reach because the geometry of ionospheric reflection simply does not cooperate.
For Pacific communications, HF’s limitations compound. The distances are vast. The ionosphere over tropical waters behaves differently than over temperate zones. Solar activity—unpredictable and uncontrollable—can degrade HF propagation for days. During the most intense phases of a crisis, when communication matters most, the ionosphere may refuse to cooperate.
Australia maintains HF networks through Defence and civilian agencies. Pacific island partners have their own HF capabilities, often legacy systems installed decades ago. But maintenance has been inconsistent. Tropical humidity corrodes equipment. Skilled operators retire without replacements. The “coconut wireless”—the informal term for Pacific oral communication networks—may prove more reliable than the electronic systems meant to supplement it.
This is not to say HF is useless. For low-bandwidth, high-priority messages—orders, warnings, coordination signals—it can function. But it cannot support the data-intensive operations that modern military coordination requires. It cannot carry intelligence products. It cannot enable the kind of real-time situational awareness that Australian and allied forces have come to expect. A force that falls back to HF is a force that has already accepted a significant degradation in capability.
What the Partners Actually Have
Australia’s Pacific partners are not passive recipients of communications infrastructure. They are sovereign nations with their own capabilities, constraints, and priorities. Understanding what they can actually do matters more than what Canberra wishes they could do.
Papua New Guinea, the largest Pacific island nation and Australia’s closest neighbor, has invested in communications resilience through the Coral Sea Cable and domestic fiber networks. But its internal infrastructure remains patchy. Many communities depend on mobile networks that themselves depend on backhaul to international cables. When the cable goes, the mobile network follows.
Fiji serves as a regional hub, with multiple cable landings and relatively developed domestic infrastructure. It has options that smaller nations lack. But Fiji’s strategic orientation has shifted in recent years, with closer ties to China and occasional friction with Australia. In a Taiwan crisis, Fiji’s cooperation cannot be assumed.
The Solomon Islands present the starkest challenge. The 2022 security agreement with China signaled a willingness to diversify partnerships away from traditional Western alignment. Communications infrastructure funded by Australia now coexists with Chinese-built facilities. In a crisis, the Solomon Islands government might face competing pressures—and might not resolve them in Australia’s favor.
Across the Pacific, a pattern emerges. Australia has invested heavily in physical infrastructure—cables, patrol boats, communications equipment. But infrastructure without institutional alignment is hardware without software. The Pacific Fusion Centre, established in Vanuatu to enhance regional information sharing, represents one attempt to build the institutional layer. But its effectiveness depends on trust relationships that take years to develop and can erode in moments.
The Wantok system—the traditional Pacific network of reciprocal obligation based on kinship and shared language—offers a counterpoint to formal institutional arrangements. Wantok networks move information through personal relationships rather than official channels. They are resilient to technical disruption because they do not depend on technology. In a communications crisis, the village chief who walks to the next village may prove more reliable than the satellite terminal that no one knows how to operate.
The Legal Vacuum
International law provides surprisingly little protection for undersea cables during armed conflict. UNCLOS establishes peacetime obligations—states must criminalize cable damage, must not interfere with repair operations, must allow cable-laying in exclusive economic zones. But these obligations assume good faith among major powers. They provide no enforcement mechanism when good faith disappears.
The International Law Association’s 2022 report on submarine cables identified critical gaps in the legal framework. Flag-state jurisdiction means that a vessel cutting cables answers only to its own nation’s courts. Coastal states cannot detain suspected saboteurs in international waters. The law becomes more permissive precisely when stakes are highest.
Australia’s domestic framework is more robust. The Security of Critical Infrastructure Act 2018, amended in 2024, designates submarine cables as critical infrastructure requiring risk management programs and incident reporting. The Critical Infrastructure Security Centre oversees compliance. But domestic law cannot compel foreign actors to behave, and it cannot repair cables that have been deliberately severed in international waters.
The insurance dimension adds another layer of fragility. As Network Computing has reported, subsea cable insurance markets are tightening as geopolitical risks increase. Lloyd’s underwriters increasingly exclude sabotage from standard policies. If cables become uninsurable against their primary threat, the economics of maintaining and repairing them shift dramatically. States may find themselves as insurers of last resort—a role few have budgeted for.
The Repair Problem
Severing cables is easy. Repairing them is hard.
The global fleet of cable repair ships numbers in the dozens. They are specialized vessels, expensive to operate, and in constant demand for routine maintenance. In a crisis affecting multiple cables simultaneously, repair capacity would be immediately overwhelmed. Wait times measured in weeks or months would become the norm.
Geography compounds the challenge. Repair ships must reach the damage site, locate the break, recover the cable from the seafloor, splice in new sections, and re-lay the repaired cable. In deep water, this process takes days even in ideal conditions. In contested waters, it may be impossible.
Pre-positioning repair assets could reduce response times. But deploying repair vessels to potential conflict zones before a crisis breaks carries its own risks. It signals expectations of conflict. It may provoke the very attack it is meant to deter. The repair ship that arrives early becomes a target; the repair ship that arrives late becomes irrelevant.
The Western Pacific typhoon season adds a final complication. Storms that would normally delay repair operations also provide plausible deniability for deliberate cable cuts. A cable that fails during a typhoon might have been severed by debris, by anchor drag, by any number of natural causes. Attribution becomes impossible. Response becomes paralyzed by uncertainty.
What Resilience Would Actually Require
True communications resilience for Australia and its Pacific partners would require investments that no government has yet been willing to make.
First, redundancy. Not one cable per route, but three or four, with diverse physical paths that cannot all be severed by a single actor in a single operation. The cost would be measured in billions. The commercial case is weak—peacetime traffic does not require such redundancy. Only strategic logic justifies the expense.
Second, hardened satellite capacity. Not commercial constellations subject to American priorities, but sovereign or allied-controlled systems with anti-jamming capabilities and guaranteed access during crisis. Australia’s 2024 National Defence Strategy moved in this direction, but implementation timelines stretch into the 2030s.
Third, distributed ground infrastructure. HF networks that actually work, with trained operators, maintained equipment, and realistic exercise programs. Satellite ground stations dispersed across multiple Pacific locations, not concentrated in a few vulnerable sites. Backup power systems that can sustain operations for weeks, not hours.
Fourth, institutional depth. Not just hardware, but relationships. Personnel exchanges that build trust before crisis. Joint exercises that reveal gaps while there is time to fix them. Intelligence sharing arrangements that survive political transitions. The Pacific Fusion Centre is a start. It is not enough.
Fifth, honest planning. Exercises that assume cables are cut, satellites are jammed, and HF propagation is degraded—simultaneously. Plans that account for partners who may not cooperate, equipment that may not function, and timelines that may not hold. The comfortable assumption that something will work must give way to the uncomfortable question of what happens when nothing does.
The Coming Test
A Taiwan crisis would stress every element of Australia’s Pacific communications architecture. The scenario is not a matter of if but when—experts assess a 57-67% likelihood of a major crisis in the near term.
In such a crisis, Australia would face competing demands. Support American and allied operations in the Taiwan Strait. Maintain coordination with Pacific partners who may be targeted for coercion. Sustain civilian communications for populations that depend on digital connectivity for everything from banking to health services. Preserve the intelligence relationships that inform decision-making.
Something would have to give. The question is what—and who decides.
The honest answer is that Australia cannot currently maintain secure, high-bandwidth communications with all its Pacific partners if China severs the cables that connect them. It can maintain some communications, with some partners, for some purposes. It can fall back to degraded modes that sacrifice speed, volume, and reliability. It can hope that allies fill gaps that it cannot fill itself.
Hope is not a strategy. But for now, it is what Australia has.
FAQ: Key Questions Answered
Q: How quickly could China sever Australia’s Pacific communications cables? A: With its newly unveiled deep-sea cable-cutting technology, China could sever multiple cables within days of deciding to act. The limiting factor is not technical capability but operational decision-making. A coordinated operation targeting three or four key cables could degrade Australia’s Pacific connectivity within 48-72 hours.
Q: Can Starlink replace submarine cables during a crisis? A: Not at scale. Commercial LEO constellations like Starlink offer resilience benefits but cannot match submarine cable bandwidth. More critically, these are American commercial assets subject to US government priorities. In a Taiwan crisis, Australia would compete with American military requirements for constellation access.
Q: What happens to Pacific island nations if cables are cut? A: Most Pacific island nations would lose international connectivity entirely, as many depend on single cables. Domestic mobile networks that rely on international backhaul would fail. Governments would fall back to HF radio and satellite phones—if they have them and if operators know how to use them. The “coconut wireless” of informal oral communication would become the primary information network.
Q: How long would cable repairs take during a conflict? A: Weeks to months at minimum. The global repair fleet is small and would be overwhelmed by simultaneous breaks. Contested waters would delay or prevent repair operations entirely. Insurance complications could further slow response. Realistic planning should assume cables remain severed for the duration of any significant conflict.
Sources & Further Reading
The analysis in this article draws on research and reporting from:
- South China Morning Post coverage of China’s cable-cutting device - Primary source on China’s deep-sea cable-cutting capability unveiled in March 2025
- Trends Research analysis of China’s undersea cable strategy - Strategic assessment of Beijing’s cable infrastructure approach
- CSIS On the Radar satellite jamming brief - Technical overview of satellite communications vulnerabilities
- Council on Foreign Relations Taiwan crisis assessment - Expert probability estimates for Taiwan Strait scenarios
- International Law Association submarine cables report - Legal framework analysis for undersea infrastructure
- Pacific Fusion Centre - Regional information sharing institution
- Australian Critical Infrastructure Security Centre - Domestic regulatory framework for telecommunications assets
- Carnegie Endowment Pacific digital transformation study - Infrastructure assessment of Pacific island nations
