Piracy and Undersea Cables: An Overlooked Interpretation of UNCLOS?

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Recent events in the Baltic Sea and other places have highlighted the importance of undersea cables and pipelines for the global economy, and indeed our daily life. Fibre optic cables are the arteries of the modern world, transmitting over 99% of intercontinental data. While electricity and gas pipelines have less global significance, they remain crucial to regional and local economies. This blog argues that attacks on subsea cables and pipelines could qualify as acts of piracy, allowing all states to board, search, and seize vessels engaged in or suspected of such attacks, as well as apprehend and prosecute those responsible.

Focus on Gaps in the Legal Framework

Most academic commentary on attacks on undersea cables and pipelines highlights gaps in the existing legal framework, particularly in the 1884 Convention for the Protection of Submarine Telegraph Cables and the 1982 United Nations Convention on the Law of the Sea (UNCLOS). Scholars and previous blogs here have suggested a United Nations Security Council (UNSC) resolution, cable protection zones, or a new international treaty to address these gaps. Others propose expanding coastal States’ enforcement powers in the EEZ, granting universal jurisdiction over intentional sabotage, and pushing for diplomatic and legal action in the EU, NATO, and IMO.

Reframing Attacks on Subsea Infrastructure as Piracy

While these suggestions are eminently reasonable, they face significant challenges: treaty negotiations and other diplomatic efforts are time-consuming and politically sensitive, UNSC resolutions risk vetoes, and the legality of cable protection zones may be questioned. Furthermore, protection zones often rely on civil penalties, offering limited deterrence.

A faster and simpler approach would be to classify attacks on undersea cables or pipelines as piracy. This is not as radical as it may seem.

Piracy, as is well known, is defined in Article 101 of UNCLOS as:

(a) Any illegal acts of violence or detention, or any act of depredation, committed for private ends by the crew or passengers of a private ship or aircraft, and directed:
(i) on the high seas, against another ship or aircraft, or against persons or property on board such ship or aircraft;
(ii) against a ship, aircraft, persons, or property in a place outside the jurisdiction of any State.

This definition is complex and has generated extensive legal debate. Most scholars agree that piracy has four key elements:

1. An illegal act of violence;

2. Committed for private ends;

3. Against another ship (the so-called ‘two-ship requirement’);

4. On the high seas or in a place outside the jurisdiction of any State.

In the Arctic Sunrise arbitration, it was stated that an ‘essential requirement of Article 101 is that the act of piracy be directed against another ship’ (para 238). However, this traditional interpretation appears to conflate the requirements of subparagraph (i) and (ii) and fails to account for the significance of the disjunctive ‘or’ in the text.

Article 101(a)(i) explicitly requires an act to be committed ‘against another ship or aircraft’, implying a two-ship requirement. By contrast, Article 101(a)(ii) omits this condition and instead refers to acts committed ‘against a ship, aircraft, persons, or property in a place outside the jurisdiction of any State.’ (Emphasis added). Thus, based on its ordinary meaning, piracy could be interpreted as:

Any illegal acts of violence… or any act of depredation, committed for private ends by the crew… of a private ship… and directed against… property in a place outside the jurisdiction of any State.

This interpretation is not new. The correct reading of UNCLOS and its 1958 predecessor has been debated for decades (ILA, para 49).

Historical Development of Article 101

The codification of Article 101 dates back to 1924, when the League of Nations tasked a Committee of Experts with identifying legal issues for international regulation, including piracy. This led Harvard Law School to conduct research, culminating in the 1932 Harvard Draft Convention on Piracy.

In 1954, the International Law Commission (ILC) drafted the Regime of the High Seas, forming the basis for the 1958 Convention on the High Seas, which contained six articles on piracy that largely replicate the Harvard Draft. However, Article 101(a)(ii) was added by the ILC. These provisions were later incorporated into UNCLOS with only minor modifications.

In fact, there was limited interest in piracy during the negotiations of both the 1958 Convention and UNCLOS, and much of the confusion regarding the two-ship requirement seems to stem from discussions in the ILC.

The Debate on the Two-Ship Requirement

The debate over the two-ship requirement primarily focused on distinguishing ‘piracy’ from ‘mutiny’ and not on attacks against infrastructure. The ILC included Article 101(a)(ii) to encompass acts against persons or property ‘on an island constituting terra nullius or on the shores of an unoccupied territory.’ (ILC Commentary, Article 39) The discussion was mainly policy-driven, with no reference to case law or accepted legal rules.

Some scholars, including Gilfoyle, Paige, and McLaughlin, have already supported a broad interpretation of Article 101(a)(ii), finding that:

Depredations against submarine cables in the high seas by non-state actors may constitute piracy…

This interpretation is supported both by the ordinary meaning of Article 101(a)(ii) and its drafting history, though it does not seem to be reflected in state practice.

The best-known counterexample is the 1985 hijacking of the Italian cruise ship Achille Lauro. This incident has traditionally not been considered piracy for two reasons: first, because the hijackers were onboard Achille Lauro, meaning the two-ship requirement was not met; and second, their actions were politically motivated rather than driven by private ends.

To fall within the scope of Article 101(a)(ii) any attack would still have to fulfil the other traditional elements, viz., an ‘illegal act of violence’, presumably referring to the law of the state exercising jurisdiction; committed for ‘private ends’, which rules out acts attributable to a State; and, it would have to be ‘outside the jurisdiction of any State’. The latter seems to exclude acts committed in the exclusive economic zone (EEZ). But Article 58(2) of UNCLOS suggests the contrary by stipulating that ‘Articles 88 to 115… apply to the exclusive economic zone…’ This includes Article 101 and piracy must therefore only take place outside any State’s territorial sea.

Advantages of a Broad Interpretation

There are differing views on whether Article 101 of UNCLOS creates an international crime or merely provides a basis for exercising legislative and adjudicative jurisdiction. It is submitted that the latter is the case. This means that piracy suspects must be tried in domestic courts under domestic law. Nevertheless, classifying attacks on undersea cables or pipelines as an act of piracy offers several advantages. First, subject to the provision of domestic law, it would allow all States to arrest and prosecute suspected pirates (UNCLOS Art 105). Second, it avoids delays and political obstacles associated with treaty negotiations or potential UNSC vetoes. Third, it avoids the militarisation of cable and pipeline security. In fact, the ‘private ends’ requirement rules out any State or State official act, and saboteurs mandated by a State would therefore not be covered. The same is true of acts committed by a government vessel or warship, unless its crew mutinies (UNCLOS, Art 102). Admittedly, this limitation reduces the scope of piracy, but it also reduces the risk of unintended escalation. Even so, boarding a foreign-flagged vessel – even if a State denies involvement in an attack – is not without risk. A state that denies involvement in an attack could not, however, legally object to the boarding, searching, and seizure of a vessel engaged in or suspected of engaging in piracy. Nor could it object to the prosecution of persons suspected to be engaged in such acts, as confirmed by UNSC resolution 1816 (2018).

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Alexander Lott says

March 6, 2025

Dear Jacques,

Thank you for this important and highly relevant contribution. I am working on the question you addressed, too (I touched upon this matter in a post for the Articles of War in the wake of the C-Lion1 incident in November). In my view, the concept of piracy under Art 101(a)(ii) of UNCLOS could, in principle, be interpreted dynamically.

However, the provision also stipulates that piracy needs to include the following elements: “any illegal acts of violence or detention, or any act of depredation, committed for private ends”. It might be more difficult to meet these criteria, since it seems to me that the damaging of submarine cables and pipelines is mostly not committed for private ends, even if it might be considered an act of violence. In the context of hybrid warfare at sea, States rather than private actors benefit from the breaking or damaging of critical offshore infrastructure of their perceived adversaries. But it might be possible to overcome this by arguing that if the coastal State has information that the suspected ship’s crew member(s) might have been paid for damaging property in the EEZ or on the high seas by anchor-dragging (e.g., for dropping the anchor at a certain place), then this could bring their actions under the definition of piracy. Do you think that this sort of line of reasoning might grant the coastal State universal jurisdiction for interdicting the ship?

Nonetheless, eventually, this matter is complicated by the fact that when conducting hybrid operations, States tend to seek to maintain plausible deniability for their involvement in the operations to avoid their responsibility for internationally wrongful acts and it would be, ultimately, very difficult to prove that the anchor-dragging was committed for private ends.

Would you like to share your view on this?

With kindest regards,
Alexander

Jean Paul Pierini says

March 6, 2025

Dear Jacques,
Thank you for bringing up such an intriguing question. Article 101(a)(ii) is from time to time discussed in respect of the departure of the internationally agreed definition of piracy from the two ships (or aircraft and combinations thereof) requirement, and accordingly encompassing the depredation of submarine cables. The interpretation endorsed, as you mentioned, in its third report by the International Law Association.
However, it does not seem that such an interpretation is supported by the drafting wording of the provision or its drafting history. The League of Nations Committee of Experts for the Progressive Codification of International Law (Questionnaire n. 6) approached the issue, stressing that piracy occurs only on the high seas and that pirates attack merchant ships of any and every nation without making any distinction. The pirate was described as a sea robber, pillaging by force of arms, stealing or destroying the property of others, and committing outrages of all kinds upon individuals. However, the Committee, by recalling three times that piracy was a danger to shipping and commerce of all nations, implicitly recognised the two ships requirement and didn’t leave much room for what you argue from article 101(a)(ii). The 1932 Harvard Draft Convention on Piracy, in its Comment to Article 3, mentions the Reply of Romania to the above Questionnaire on Piracy. The said Reply made the example of brigands attacking and plundering a convoy or a caravan “in some unowned territory” and proposed to replace the reference to the “high seas” with that of a “place not subject to the sovereignty of any State”. The term we find some twenty years later in the ILC Draft you mentioned. However, the said Draft did not “replace” the reference to the high seas as suggested in 1927 and instead inserted the additional provision about places outside the jurisdiction of any State. References to piracy in “unappropriated land” were already to be found in W.E. Hall’s International Law.
Article 3 of the Harvard Draft Convention required the act of violence to be “connected with an attack on or from the sea or in or from the air” and further stated that “If the act is connected with an attack that starts from on board a ship, either that ship or another ship that is involved must be a pirate ship or a ship without national character.” The drafters of the Commentary were well aware of Fields 1876 Draft Code (which is reproduced in Appendix 3 to the Comments) setting (art. 83) the destruction of telegraphic cable on the same footing with piracy, but the proposal didn’t find its way into the Draft Convention. They were also aware of the 1862 U.S. proposal for a Convention equating piracy and damaging cables that was discussed at length in the 1879 Renault Report that influenced the 1884 Paris Convention.
In the ’50s, the ILC considered the two ships requirement in respect of piracy on the high seas and imagined acts of piracy “from the sea” on unappropriated land (or on the icepack?) outside the jurisdiction of any State as you acknowledge. There was little, if any, discussion at the diplomatic conference, and the Geneva wording found its way into the Montego Bay Convention.
As to the actual wording the provisions under Article 101(a)(i) and (ii) are distinct in respect of the “locus”. The text does not seem to support readings equating the locus … and creating a “doppelganger” of piracy on the high seas … but without the two ships requirement. The ordinary wording of Article 101(a)(ii) reflects rather the original purpose or the norm. Art. 101(a)(ii) may eventually encompass the depredation of cables … on unappropriated land. Further it doesn't seem that a systematic interpretation of UNCLOS could reconcile art. 113 with the proposed reading article 101.
I agree with the need to reinforce the protection of cables, but Article 101(a)(ii) cannot be stretched to that extent.

Jacques Hartmann says

March 7, 2025

Dear Alexander and Jean-Paul,

Many thanks for your thoughtful responses. This is exactly the kind of interaction I was hoping for.

Re: Alexander
As you know, scholars have long debated the private ends requirement. The ILA provides a good overview of the debate in A/CN.4/767. Scholars generally fall into three main groups. One group argues that piracy includes any unauthorised violence, regardless of motive, as long as it lacks state backing. Another holds that piracy excludes political acts, such as terrorism, since these are considered public, not private, in nature. A third, more flexible approach suggests evaluating cases individually, focusing on whether an act threatens international shipping rather than its intent.

I personally align with the first group. This is why I suggested that the hybrid nature of attacks could be exploited, as they cannot be clearly attributed to a state.

That said, I also find your argument that payment to individuals for sabotage could bring these actions under the definition of piracy interesting. However, this interpretation does not easily align with the first group’s position. I would be happy to discuss this further.

Re: Jean-Paul
Your references to the 1932 Harvard Draft Convention and earlier discussions on piracy are certainly valuable in tracing the historical evolution of the concept. However, I am less persuaded by their relevance to the interpretation of Article 101, as our primary focus should be on the intent of the drafters of the 1958 and 1982 conventions.

Moreover, as you know, treaty negotiations serve only as a supplementary means of interpretation. This reinforces the idea that treaty interpretation must be guided primarily by the ordinary meaning of the text, within its context and purpose, rather than by assumptions drawn from drafting history alone.

In my view, the biggest obstacle to the suggested interpretation is the lack of state practice supporting it.

I look forward to continuing this discussion.

Best regards,

Jacques