Unseen hands, shadow fleets and undersea cable sabotage

This article was originally published by Pacific Forum. It is republished with permission.

As the mysteries behind high-profile undersea cable ruptures in the Baltic Sea and Taiwan Strait remain unsolved, scrutiny over Russian and Chinese “shadow fleet” activity has only intensified throughout 2025, doing little to quell speculation about intentional sabotage.

Shadow fleets, which mainly came to prominence following Russia’s 2022 invasion of Ukraine, are primarily associated with the movement of goods targeted by sanctions, particularly oil.

To evade detection, sanctioned nations operate vessels that are managed, owned, and registered across multiple jurisdictions, and which bear foreign flags concealing their identities (or indeed, no flag at all).

Amid rising geopolitical tensions—and a corresponding rise in global sanctions—shadow fleets are continuing to grow substantially in number. Despite concurrent efforts to sanction shadow fleets themselves, the relentless expansion of these fleets underscores their usefulness in helping sanctioned nations work covertly to gain strategic advantages alongside circumventing restrictions.

Covert activities are by no means confined to circumventing restrictions on trade, and are increasingly associated with attacks on critical maritime infrastructure. Despite growing suspicions, deliberate sabotage remains difficult to prove and attribute, particularly as convoluted registration frameworks provide shadow fleets with plausible deniability.

Given their indispensability to global connectivity, undersea communication cables are unsurprisingly an attractive target for disruption, and enlarged shadow fleets will almost certainly exacerbate security risks. However, as more communication cables descend underwater, a less visible factor behind the ascendance of shadow fleets lies in the ownership structure of these cables.

Specifically, undersea communication cable systems are predominantly owned by large private corporations and consortia. Three firms, SubCom (United States), NEC (Japan), and ASN (France), were estimated to hold 87% of the global undersea cable market in 2021, while Google, Meta, Amazon, and Microsoft are increasingly building new cables.

Within private ownership structures, undersea cables are primarily viewed through the lens of profitability. This is especially true in the US, where Big Tech monopolies are no longer merely content producers but also owners of cables. Consequently, these companies now seek to exercise complete dominance in the cable supply chain, potentially generating higher long-term financial returns.

Preoccupations with profitability come at the expense of security. Neither a dedicated national agency for undersea cables, nor a comprehensive framework for maintenance, protection, and repair currently exist in the US.

While some US government funding has been provided for ships with cable repair capabilities, cable repair remains far less lucrative than cable construction, meaning little financial incentive for private companies to increase or improve repair fleets. Globally, there exist just 22 ships exclusively designated for cable repair, many of which are approaching obsolescence.

Compared with private firms, the public sector’s investment in undersea cables is currently minimal (maybe with the exception of China, noted below). The private sector’s dominance in undersea cables also threatens to undermine legal frameworks for cable protection.

While the state sector oversees relevant legislative measures, such as Articles 113 to 115 of the United Nations Convention on the Law of the Sea, inconsistencies and gaps appear in their implementation. In particular, maritime law enforcement faces myriad challenges compared with equivalent laws on land, including difficulties in determining jurisdiction in international waters and in detecting violations due to the sheer size of the ocean.

Instead, the preeminence of the private sector in the undersea cable market enables companies to dictate their own norms around undersea cables. These norms are not always favourable to nation-states.

Notably, as cable owners determine the locations of new cable projects (as well as which nations these cables connect to), companies proactively shape the physical geography of the Internet beyond the purview of the state, perhaps even granting such companies a degree of geopolitical leverage.

In this regard, the development of influential private sector norms around undersea cables would further weaken the state’s ability to enforce already deficient laws. In any case, states are unlikely to be the sole or primary authority over maritime issues, providing private companies with ample room to act in their own self-interest at sea—in ways not necessarily conducive to the protection of critical infrastructure.

Occasionally, private sector interests may in fact align with those of sanctioned states, even if only coincidentally. Though some companies are motivated exclusively by the pursuit of profit, a willingness to engage in business with sanctioned nations has geopolitical implications, unintentional or otherwise.

This includes private shipowners willing to sell vessels for the eventual purpose of being used for shadow fleets. In some instances, sellers originating from nations participating in global sanctions are nevertheless incentivised to sell ships to sanctioned states, due to the prospect of considerably larger profits than they would otherwise receive for ageing, poorly-maintained vessels.

Moreover, to avoid legal consequences of violating sanctions, private companies in the above nations are unlikely to directly provide sanctioned states with ships. Rather, these shipowners often first sell vessels to shell companies registered in non-participating jurisdictions in international sanctions regimes (such as India and Seychelles), before subsequently being operated by sanctioned states themselves.

In doing so, these companies play a key role in complicating shadow fleet ownership structures, which in turn helps to obscure the identities of shadow fleet vessels to the benefit of sanctioned states, and possibly facilitating covert sabotage operations.

Recent developments, such as Russia’s use of fighter jets to protect shadow fleet ships, and China’s unveiling of a specialised subsea cable-cutting vessel, underscore linkages between shadow fleets and sanctioned states, as well as a rising urgency to secure critical maritime infrastructure.

While its growing gray-zone capabilities suggest a more complex reality, China’s efforts to publicly position itself as a protector of such infrastructure demonstrate an strategic attempt to seize the narrative and shape public opinion around undersea cables.

In response, nations have long discussed expanding cable capacity and building redundancy. However, these efforts remain hampered by the continued dominance of private firms in cable ownership and repair. Initiatives like Team Telecom offer some oversight regarding risks arising from foreign ownership, but do little to address the fundamental imbalance in public-private control.

While ambitious deterrence measures and sanctions against shadow fleets are also proposed, an even firmer solution lies in reforming ownership structures. Multi-firm ownership models and international cooperation are positive steps, but insufficient without far greater public sector engagement. Rather concerningly, looming federal budget cuts in cybersecurity and infrastructure risk further entrenching the private sector’s control in the US.

To counter this trend, states should invest in sovereign cable repair ships and monitoring capabilities to match the strategic projection of rivals. Doing so would not only enhance cable resilience but also empower states to enforce maritime law more robustly, as opposed to relying on norms shaped by commercial interests. States around the world should also remain aware of the potential to leverage undersea cables as a tool of diplomatic and economic influence.

Put simply, the protection of undersea cables is not just a technical or commercial matter, but a geopolitical imperative. Should more oversight and governance of the arteries of global communication be the goal, the public sector must first initiate structural changes in cable ownership frameworks.

Sean Tan (sean.tanyj@ntu.edu.sg) is a senior analyst at the Centre of Excellence for National Security at the S. Rajaratnam School of International Studies in Singapore. With a keen interest in non-traditional security matters, Tan is engaged with work in this space, including disinformation, foreign interference, attacks on critical infrastructure, hybrid threats and corporate censorship.