Taiwan’s undersea communications cables keep getting cut. In January, Xingshun 39 — a Tanzanian-flagged vessel controlled by a Hong Kong company and crewed by Chinese nationals — disabled its tracking system before dragging its anchor over a cable, severing a key link between Taiwan, Asia, and the United States. Days later, the Taiwan Coast Guard thwarted a cable-cutting attempt by a Mongolian-flagged ship with a Chinese name. In February, Hongtai 58, a Togolese-flagged vessel with a Chinese crew, severed a cable connecting Taiwan and the Penghu Islands. Its voyage history revealed ties to Chinese interests, frequent name and flag changes, and deliberate efforts to obscure ownership.
Beijing claims these are routine accidents, but the pattern, precision, and persistence of such incidents point to deliberate sabotage — a calculated prelude to a potential conflict in the Taiwan Strait. To escape accountability, China is employing a form of lawfare best described as civil-exploitation lawfare: the manipulation of international law governing civilian maritime activity to mask state-backed malign behavior.
Undersea cables are a focal point of Chinese strategy because they form the backbone of global communications, supporting everything from routine internet use to global financial transactions and secure military communications. Taiwan serves as a critical node in undersea communications, connected by 14 international cables to the United States and countries across East Asia. A major attack on Taiwan’s undersea infrastructure could destabilize the global economy and force high-stakes decisions on defending the island under conditions of digital isolation.
To mitigate this risk, U.S. policymakers should adopt a strategy to enhance cable security by countering China’s “shadow fleet” — a network of vessels whose ties to China are deliberately concealed, enabling them to threaten undersea infrastructure while preserving deniability for Beijing. Such a strategy should involve building a maritime security coalition, closing gaps in international law, leveraging information transparency, applying targeted diplomatic pressure, strengthening Taiwan’s maritime defenses, and using legal tools as instruments of deterrence.
China’s Shadow Fleet Exploits Legal Ambiguity
Operating behind layers of deception, China’s shadow fleet plays a critical role in Beijing’s preparations for a potential Taiwan invasion. Disguised as fishing trawlers, dredgers, and cargo ships, shadow vessels have been increasingly linked to reconnaissance and undersea cable sabotage in the waters surrounding Taiwan. These ships exploit flags of convenience, shell companies, and opaque funding to conceal their true affiliation, origin, and intent, while frequently changing names, flags, and ownership to obfuscate their identities.
At sea, shadow vessels deactivate their automatic identification system transponders, avoid port calls, and engage in ship-to-ship transfers to evade port inspections and dodge foreign legal jurisdiction. Dense traffic in the Taiwan Strait offers ideal cover, enabling shadow vessels to blend seamlessly with thousands of legitimate ships operating in the area. In congested waters like these, accidental cable damage is plausible, but the recurring, well-placed, and seemingly systematic nature of recent incidents leaves little doubt about intent, despite Beijing’s denials.
The current trend traces back to February 2023, when Chinese shadow vessels severed two undersea cables linking Taiwan’s main island to its outer islands near the Chinese coast, cutting internet access for 13,000 residents for nearly two months. Since then, China’s shadow fleet has grown, with nearly 100 suspected shadow vessels now operating in waters near Taiwan. With this expansion, the frequency of suspected sabotage has also increased.
By exploiting the guise of civilian shipping, China is leveraging a lawfare tactic referred to here as civil-exploitation lawfare. Central to this tactic, Beijing cloaks its sponsorship behind the principle of exclusive flag state jurisdiction, which under the United Nations Convention on the Law of the Sea (UNCLOS), grants primary authority over a vessel to the country where it is registered, limiting other states’ jurisdiction beyond their territorial seas. By registering vessels in states that lack the will or capacity for enforcement, China ensures that its shadow fleet can operate with near impunity below the threshold of war, consistent with its broader military-civil fusion objectives. Crucially, the shadow fleet’s commercial veneer blurs the legal distinction between civilian and military objects. This calculated ambiguity masks hostile intent, complicating threat assessments and response decisions by China’s law-abiding adversaries.
Undersea cables that lie beyond coastal state jurisdiction are particularly vulnerable to this type of lawfare. UNCLOS prohibits damage to undersea cables but lacks enforcement mechanisms, relying on flag states that are often unwilling or unable to act. Moreover, despite UNCLOS requiring states to criminalize cable damage, many states either lack such laws or do not enforce them. The 1884 Submarine Cable Convention permits foreign warships to inspect the documentation of suspected cable cutters, but enforcement still rests with the flag state, and only 36 nations — including the United States but not China — have ratified the treaty. These weaknesses in international law breed opportunity for China’s shadow fleet to sever cables with minimal risk, as limited recourse exists when flag states fail to act.
A Subsea Pressure Campaign
China aims to prepare the battlespace for potential conflict by eroding Taiwan’s resilience. Its massive shadow fleet complements other gray zone tools to exhaust Taiwan’s physical defenses and psychological resolve, reinforcing perceptions of Chinese dominance and the futility of resistance. If not actively targeting undersea cables, shadow vessels contribute to persistent surveillance of Taiwan’s subsea infrastructure, allowing China to map vulnerabilities for future attacks. As a result, Taipei faces an unrelenting security dilemma, forced to discern between legitimate commercial traffic and latent threats to its territory. This challenge demands vigilance, critical thinking, and resources — already stretched thin as Taiwan contends with daily threats across all domains, and increasingly aggressive Chinese invasion rehearsals.
Each cable disruption also yields valuable intelligence for Beijing, revealing how quickly Taiwan repairs damage, what backup systems it employs, and how the United States and others may respond. Armed with insight into reaction patterns and vulnerabilities, Beijing can prepare for a decisive strike on undersea systems at a moment of its choosing. Meanwhile, the threat of subsea sabotage injects uncertainty into Taiwan’s information environment, potentially triggering economic volatility in a digitally dependent trade and financial sector. Even temporary internet blackouts erode public confidence, advancing Beijing’s objective of undermining Taiwan’s societal cohesion from within.
If conflict erupts in the Taiwan Strait, undersea cables would likely be among China’s first targets. Shadow vessels could be deployed to sever undersea cables as part of a broader shaping operation — actions that may obscure the onset of broader hostilities. Aligned with Chinese military doctrine on systems destruction warfare — which aims to paralyze critical operational and support networks — undersea cable attacks could be synchronized with actions in other domains to degrade command and control, disrupt defense mobilization, and obstruct international response coordination. Such attacks could also enable Beijing to manipulate information flow, forcing Taiwan to rely on vulnerable channels susceptible to Chinese access.
Recognizing the strategic importance of undersea cables, China is prioritizing the resilience of its own network. One Chinese scholar described this as a multipronged approach involving legal frameworks, technological innovation, and infrastructure development. To ensure it can defend and rapidly restore its cables, Chinese civil authorities have conducted extensive cable repair drills in tandem with military exercises near Pingtan, one of the mainland’s closest points to Taiwan and a likely staging area for a cross-Strait invasion. Meanwhile, as China improves its undersea defenses, it recently unveiled a deep-sea cable-cutting device designed for integration with advanced submersibles. The timing of this disclosure — just weeks after the February cable-cutting incident in the Taiwan Strait — signals that undersea cables are squarely in the crosshairs during a potential conflict.
As Beijing’s subsea pressure campaign intensifies, Taipei has responded by establishing an interagency response platform and advancing legislative reforms, upgraded security protocols, and deployment of the Submarine Cable Automatic Warning System to improve threat detection and real-time alerting. The Taiwan Coast Guard has also increased vessel inspections and monitoring. Although these actions are important, the scale and complexity of the challenge exceed Taiwan’s capacity, especially as risks extend beyond its territorial sea, implicating regional and global interests.
Indeed, China’s actions reflect a broader pattern of maritime lawlessness, evident in the expansion of Russia’s shadow fleet and suspected Sino-Russian coordination in targeting European undersea cables. A major Chinese attack on the trans-Pacific cable network near Taiwan could trigger far-reaching consequences: destabilizing the global economy and potentially marking a shift toward military conflict. If this happens, the United States will face critical decisions on how to respond to Chinese aggression, complicated by Taiwan’s digital isolation. Preventing this scenario calls for swift U.S. action to counter China’s shadow fleet and protect vital undersea infrastructure.
A U.S. Strategy Focused on Deterrence
The United States should elevate undersea cable security in the Indo-Pacific as a strategic priority. To address the specific threat in the Taiwan Strait, Washington should focus on deterrence: dissuading China from attacking undersea cables by constraining the shadow fleet’s expansion and freedom of action, complicating sabotage efforts through enhanced maritime security, and imposing consequences for violations. Achieving this will require a coordinated interagency effort and collaboration with allies and partners. The following is a breakdown of several actionable proposals for U.S. policymakers.
Forge A Maritime Security Coalition
Existing multilateral frameworks provide a foundation for expanded cooperation, with the 2024 New York Joint Statement on the Security and Resilience of Undersea Cables (“New York Statement”) — endorsed by 17 nations including the United States, Australia, and Japan — serving as a potential catalyst. The New York Statement outlines a set of principles reaffirming support for international law, committing to cable resilience, and condemning intentional interference. The Quad Partnership for Cable Connectivity and Resilience—launched in 2023 by the United States, India, Japan, and Australia—advances similar goals and led to the establishment of the Cable Connectivity and Resilience Centre in Australia, which now serves as a regional hub for technical support and training. Importantly, the Association of Southeast Asian Nations (ASEAN) has also begun to engage more directly on the issue, with both the ASEAN secretary-general and ASEAN defense ministers publicly emphasizing the strategic importance of undersea cable security.
The G7’s March pledge to create a “Shadow Fleet Task Force” marks a step forward in operationalizing a coalition response. To advance these efforts, the United States should convene a group of international experts to develop recommendations specific to the Indo-Pacific region, drawing on the example of U.S.-European expert collaboration to counter Russia’s shadow fleet in the Baltic Sea. One possible approach is to establish a U.S.-led Multinational Maritime Security Construct, modeled on NATO’s Baltic Sentry and the United Kingdom–led Nordic Warden task force, which leverages an artificial intelligence–enabled tool to track Russia’s shadow fleet and related threats to European undersea cables.
A maritime security coalition in the Indo-Pacific could oppose China’s civil-exploitation lawfare by promoting transparency and the rule of law through partnered operations, information sharing, and unified public messaging grounded in UNCLOS. It might also indirectly support broader deterrence objectives through patrols in or near the Taiwan Strait, possibly undermining Beijing’s confidence in its counter-intervention strategy. Participating nations could join in monitoring critical cable nodes, querying suspicious vessels, and engaging constructively with flag states and regional stakeholders to counter shadow fleet operations.
Close Legal Gaps at Sea
To mitigate gaps in international law, the United States should promote norm-setting by institutions such as the International Maritime Organization (IMO) and Tokyo Memorandum of Understanding (Tokyo MOU). Broad endorsement of IMO Resolution A.1192(33), which provides guidelines for curbing the rise of shadow fleets, is an important step. Washington should publicly back the resolution, urge others to do the same, and press the IMO to implement even stronger measures focused on transparency and accountability.
At the regional level, U.S. officials should encourage the Tokyo MOU’s consortium of 22 Indo-Pacific maritime authorities to follow the Black Sea MOU’s lead by incorporating the resolution into its Port State Control Manual and expanding its public database of underperforming vessels. As part of this effort, the United States should advocate for Taiwan’s inclusion in both the IMO and Tokyo MOU, recognizing its strategic location and critical role in global shipping. Even limited participation, such as observer status, could enhance regional maritime domain awareness, technical collaboration, and response capacity.
Industry stakeholders and non-governmental organizations offer additional channels for the United States to institutionalize maritime norms. For example, in coordination with interagency partners, the U.S. Navy, through its Naval Seafloor Cable Protection Office, could engage shipping companies, maritime insurers, and the International Cable Protection Committee to spotlight China’s shadow fleet and undersea infrastructure threats in the Taiwan Strait. These efforts could help shape best practices in cable security for consideration by the International Telecommunication Union, strengthen corporate compliance frameworks, and encourage insurers to adopt policies that penalize deliberate or negligent activity. Through such initiatives, the United States can drive norm-setting that incentivizes responsible conduct and enhances collaboration among flag states, port authorities, and the private-sector.
Maximize Information Transparency
The United States should harness strategic communications to uphold international law and norms and impose reputational costs on China. Joint declarations with allies such as Japan, South Korea, and Australia can help expose and oppose shadow fleet operations and threats to undersea cables. This messaging can be embedded in broader narratives on navigational freedoms and regional stability, and synchronized with multinational exercises, Taiwan Strait transits, and key leader engagements to reinforce American and allied resolve. At the same time, U.S. officials should use both public and private channels to galvanize international support for the New York Statement and IMO Resolution A.1192(33), while advancing practical areas of cooperation.
The U.S. Coast Guard and Maritime Administration can reinforce this approach by updating port state control advisories and Denial of Entry Lists to publicize shadow fleet activities and restrict domestic port access. These steps could also include notices to mariners or industry advisories identifying vessels, owners, or companies linked to China’s shadow fleet or subsea sabotage — raising awareness and increasing pressure on flag states, insurers, and shipping firms to disengage from high-risk actors. Even if shadow vessels never intend to enter U.S. waters, public designation and exposure of their ownership and corporate affiliations may help stigmatize bad behavior and bolster the information ecosystem needed to support deterrence and accountability at sea.
Apply Targeted Diplomatic Pressure
In diplomatic and military engagement, U.S. officials should underscore the strategic importance of undersea cables, emphasize concerns with China’s shadow fleet, and pressure third-party enablers to comply with laws and norms. This should include efforts to persuade flag states of convenience to adhere to UNCLOS, the New York Statement, and IMO Resolution A.1192(33), including by investigating, prosecuting, or de-flagging suspected shadow vessels — following the example set by Palau, which recently suspended three Russian shadow vessels from its registry. Noncompliance could trigger sanctions or designations by the Treasury Department’s Office of Foreign Assets Control, while compliance might be incentivized through capacity building or development assistance, reinforcing a dual-track approach that rewards lawful behavior and penalizes complicity in China’s malign activities.
Harden Taiwan’s Maritime Security
The United States should help build Taiwan’s capacity to counter China’s shadow fleet and protect its undersea cables, directly advancing U.S. interests by deterring Chinese aggression. By leveraging the U.S.-Taiwan Coast Guard MOU — facilitated through the American Institute in Taiwan — U.S. officials can support Taiwanese counterparts as they develop operational protocols tailored to specific threats. This may include assistance with contingency plans, undersea infrastructure monitoring, or employment of the Submarine Cable Automatic Warning System. U.S. advisers could also help strengthen Taiwan’s port state control measures, regulate ship-to-ship transfers, and establish warning zones or traffic separation schemes — measures consistent with the regime of innocent passage and aimed at enhancing maritime domain awareness in Taiwan’s claimed territorial sea.
These efforts should be reinforced by interagency counter-lawfare initiatives that equip maritime security practitioners with the legal tools, operational guidance, and technical expertise needed to reduce China’s maneuver space in the gray zone. Entities like the Joint Interagency Task Force West can contribute through intelligence sharing with law enforcement partners, enhancing the ability of frontline actors to detect, deter, and respond to illicit maritime activity. Together, these actions can build a more resilient regional deterrence architecture that strengthens Taiwan’s maritime security by limiting the effectiveness of China’s civil-exploitation lawfare.
Turn Law into Leverage
The United States should work with Taiwan and like-minded partners on legal strategies to impose costs on China and uphold the rule of law. For example, an UNCLOS member state like Palau — a diplomatic ally of Taiwan that is also facing Chinese pressure on its undersea infrastructure — could bring a case against China before the Permanent Court of Arbitration or the International Tribunal for the Law of the Sea, citing violations of UNCLOS obligations to prevent unlawful interference with undersea cables. Taiwan, the United States, or others could provide technical evidence or submit amicus-style input through Palau or another partner state.
Domestically, U.S. courts should exercise criminal jurisdiction if a shadow vessel deliberately damages a transnational cable that connects to U.S. territory, such as the Asia-America Gateway — following the precedent set by Taiwan’s indictment of the Chinese captain of Hongtai 58. Detained crew members could be offered leniency or protection in exchange for intelligence exposing state-sponsored sabotage. Civil litigation offers a complementary path: Washington could support lawsuits by coastal states or affected cable operators against shadow fleet owners or insurers in permissive foreign jurisdictions, including through third-party litigation funding. By advancing these legal avenues, the United States can strengthen deterrence by signaling that covert aggression will be met with concrete accountability.
Curbing Malign Behavior
These proposals are not without risk. Skeptics may caution that attributing hostile intent without definitive proof could escalate tensions or damage U.S. credibility. Chinese state media is urging restraint, warning against premature accusations. Although scrutiny of intent is warranted, the pattern of recent incidents is consistent with Chinese gray zone tactics and strains the limits of coincidence. Dismissing them as accidents risks normalizing malign behavior, weakening deterrence, and enabling continued exploitation of the ambiguity that defines shadow fleet operations. This is the essence of civil-exploitation lawfare: weaponizing procedural paralysis and a presumption of civilian innocence to erode maritime order for China’s gain.
Countering this threat calls for a comprehensive U.S. strategy — one that unites partners in a maritime security coalition, mitigates gaps in international law, increases information transparency, applies diplomatic and legal pressure, and fortifies Taiwan’s undersea defenses. These measures will help blunt Chinese coercion, reduce risk of escalation, and protect the digital lifelines that underpin global stability.
The views expressed in this post are those of the author and do not reflect the official policies or positions of the U.S. Navy, the U.S. Department of Defense, or the U.S. government.
