As Australia strengthens the protection of critical seabed infrastructure, it should draw on Taiwan’s frontline experience. Taiwan has been battling this problem for three years.
At the Shangri-La Dialogue in Singapore on 30 May, Deputy Prime Minister Richard Marles warned that ‘the seabed is becoming a battlefield’ and asked whether hostile actors may be testing response times, attribution thresholds and political will. Taiwan has confronted this operating environment since February 2023 and has accumulated practical knowledge of vessel behaviour, tracking anomalies and the limits of existing maritime enforcement tools.
As Australia strengthens its undersea capabilities through AUKUS, Taiwan’s experience offers a separate and complementary source of operational insight. This would require no change to Australia’s policy settings. It would begin with recognising the practical value of lessons already learned.
Australia has good reason to act quickly. Marles noted that around 99 percent of Australia’s internet traffic flowed through just 15 subsea cables. Financial services, health systems, communications and the wider economy depend on physical assets that are hard to protect and easy to disrupt.
Taiwan’s experience is not theoretical. On 3 January 2025, an international subsea cable off Taiwan’s northern coast was severed. Taiwanese authorities suspect that a foreign-flagged cargo vessel operating in the area was responsible. The following month, a Togo-flagged ship severed the cable linking Taiwan’s main island and the Penghu Islands. In June, a Taiwanese court jailed the vessel’s Chinese captain for three years for intentionally damaging the cable.
The conviction matters, but the broader value lies in the operational record Taiwan has built around repeated incidents. Authorities have had to assess vessels sailing under flags of convenience, unclear ownership structures, irregular tracking behaviour and prolonged activity near sensitive infrastructure. These cases don’t resolve every attribution problem but do provide a useful baseline for identifying patterns earlier and responding more effectively.
Australia has already recognised the risk. It has cable protection zones, a Cable Connectivity and Resilience Centre and investments across the Pacific. Marles has also called for stronger information sharing, better vessel monitoring, updated laws and closer use of port-state measures.
There is also a structural problem. The misinterpretation of General Assembly Resolution 2758 – which admitted the People’s Republic to the United Nations but said nothing about Taiwan’s status – has long been used to constrain Taiwan’s participation in international mechanisms, including technical forums where practical coordination matters. In technical domains, exclusion can create governance gaps: useful operational knowledge becomes harder to share and institutional blind spots easier to exploit.
Taiwan is also turning what it’s learned since 2023 into a broader offer of cooperation. In October 2025, it launched the Risk Management Initiative on International Undersea Cables, focused on risk mitigation, information sharing, systemic reform and knowledge building.
AUKUS makes this especially timely. Its first signature project under the security partnership’s Pillar Two will develop advanced payloads and enabling systems for uncrewed undersea vehicles. These systems are intended to improve protection of critical seabed infrastructure, along with surveillance and reconnaissance.
Taiwan’s experience sits outside AUKUS, but it is complementary. Years of dealing with flags of convenience, tracking anomalies and legal grey areas have produced a body of operational insight that deserves closer attention as Australia strengthens the resilience of its critical seabed infrastructure.
Marles has raised the right issue. Taiwan has already spent years working on part of the answer.
