Fadel Abdulghany
Many journalists and analysts have described Iran’s actions in the Strait of Hormuz—from closing the strait and threatening commercial vessels to requiring prior coordination for passage—as piracy. This description carries significant rhetorical weight, as it invokes the oldest classification of international crimes: the principle of “enemy of all mankind.” However, the question of whether Iran’s conduct falls under the legal definition of piracy is different from the question of whether it violates international law. The answer to the first question is no. The answer to the second is yes. Indeed, the legal consequences of this are, in many respects, more severe than those of piracy.
Piracy is formally defined in Article 101 of the United Nations Convention on the Law of the Sea, which codifies existing customary international law. This definition requires four concurrent elements: the commission of unlawful acts of violence, seizure, or plunder; that these acts be committed by the crew or passengers of a private vessel; that they be for private purposes; and that they be directed against another vessel on the high seas or outside the jurisdiction of any state. This definition was also adopted in the 1958 Geneva Convention on the High Seas, and the work of the International Law Commission on peremptory norms has further strengthened the prohibition of piracy as one such norm.
Iran’s conduct violates at least two of these criteria. The most significant obstacle is the requirement of “private intent.” Piracy, by definition, is an act committed by non-state actors for personal or financial gain. The Iranian navy, the Islamic Revolutionary Guard Corps Navy, drone operators, and mine-laying operations are all state entities operating under state command and in accordance with state policy. When a state directs violence at sea, the resulting act falls under the laws of maritime warfare, the use of force, or the laws of armed conflict, not piracy.
The geographical element is no less problematic. The Strait of Hormuz, which is about 21 nautical miles wide at its narrowest point, lies entirely within the overlapping territorial waters of Iran and Oman, both of which claim the maximum permissible territorial waters of 12 nautical miles. Attacks within territorial waters are not considered piracy under the United Nations Convention on the Law of the Sea, although they could be classified as “armed robbery of ships” under the regional instruments of the International Maritime Organization, a different legal classification.
However, the fact that the term “piracy” does not apply does not diminish the seriousness of Iran’s conduct; rather, it directs the analysis toward more appropriate legal frameworks. Articles 37 to 44 of the United Nations Convention on the Law of the Sea establish an inalienable right of transit passage through international straits. This right, which has been affirmed as part of customary international law binding on Iran, despite its non-participation in the Convention, not only prohibits formal closures but also encompasses any “functional impediment” to passage, assessed cumulatively. Thus, the combination of drone attacks, mine laying, threats, and the imposition of coordination and payment for passage constitutes this type of functional closure. Security Council resolution 2817, adopted on 11 March 2026, explicitly condemned these acts as violations of international law and serious threats to international peace and security, affirming that any attempt to impede legitimate transit passage constitutes such an act.
Some legal commentators have deliberately used the analogy of piracy as a normative argument rather than a technical classification. An analysis published in the MIT Press journal *International Security* argued that closing the Strait would constitute a grave violation of international norms, directly and significantly impacting the interests of most states, “effectively amounting to an act of piracy.” This argument uses the term “piracy” in its historical and political sense—that of inhumanity—rather than in its technical sense as defined by the United Nations Convention on the Law of the Sea. A more legally accurate formulation would be that Iran’s actions produce effects similar to piracy, in terms of the systematic disruption of freedom of navigation, the economic coercion exerted on third countries, and the detention of approximately 20,000 seafarers aboard some 2,000 vessels in an active war zone.
A distinction must be made between piracy and unlawful aggressive conduct. Universal jurisdiction applies to piracy, allowing any state to arrest and prosecute pirates regardless of the flag of the vessel from which they committed the act. However, maritime attacks by states do not trigger universal jurisdiction in the same way. The appropriate tools of response in such cases are state responsibility, countermeasures, diplomatic protest, and institutional condemnation, as demonstrated in Security Council Resolution 2817 and its potential consequences under Chapter VII. Furthermore, Iran’s actions could expose it to proceedings before the International Court of Justice for violating its customary obligations under the Law of the Sea, to claims from the flag states of the neutral vessels attacked, and potentially to scrutiny by the International Criminal Court if attacks on civilians aboard neutral merchant vessels are considered war crimes in the context of an international armed conflict.
Therefore, the fact that the official definition of piracy does not apply to Iran’s behavior does not provide it with a defensive basis, because this behavior simultaneously violates a number of non-derogable rules in the Law of the Sea, the Law of Maritime Warfare, and the Law of the Use of Force, and the formulation of the international response has already been made in a way that may support further collective action within the framework of the United Nations Charter.
