The Strait of Hormuz, a strategic crossroads for global energy trade, presents itself today as a true laboratory of contemporary international law. Connecting the Persian Gulf to the Gulf of Oman, it constitutes an obligatory passage for almost a fifth of the world’s oil transported by sea. In this context, it is not surprising that the armed conflict of 2026 between the United States and Iran will test the normativity of the law of the straits. The central question therefore is: does international law authorize a restriction of transit passage during times of war?
This question is not only theoretical. The closure or threat of closure of the strait could have immediate repercussions on the global economy, energy security and regional geopolitical balance. However, international law has clearly affirmed that freedom of passage constitutes a fundamental norm, preserving the collective interest of the international community, even in the face of the national security imperatives of riparian states.
Passage in transit: a fundamental legal regime
Since the 1982 United Nations Convention on the Law of the Sea (UNCLOS), international law has established a specific regime applicable to international straits. Article 38 of the convention defines transit passage as “the exercise of freedom of navigation and overflight for the purposes of continuous and rapid transit.” This definition highlights three essential characteristics: the functional purpose of transit, its universal applicability and its non-acceptability of suspension. In other words, passage must be ensured in a continuous and rapid manner, without the territorial sovereignty of the riparian States being able to constitute a legal obstacle. This design is not just a conventional innovation. The doctrine underlines the importance of this regime as a structural limit to sovereignty. Jean-Pierre Dupuy underlines that “transit passage marks the emergence of a structural limitation of territorial sovereignty for the benefit of the general interest of the international community” (Dupuy, Droit international public, Dalloz). Alain Pellet adds: “The law of the straits has reached a degree of consolidation such that it cannot be called into question by the sole will of a coastal state” (Pellet, Droit international public, LGDJ).
International jurisprudence confirms this orientation. The Corfu Strait affair (1949) had already illustrated that a state could not hinder the passage of neutral ships in an international strait, even in times of tension. More recently, the M/V Saiga case (1999) reaffirmed that freedom of navigation constitutes an objective right, which does not depend on the specific agreement of coastal states. These decisions contribute to making transit passage a true structuring principle of maritime law, with an almost imperative value.
Confrontation with armed conflict
The question that arises today is that of the articulation between maritime law and the law of armed conflicts. Contrary to an ancient conception according to which war suspended the law, it is today recognized that the law of the sea continues to apply in times of conflict. Patrick Daillier thus notes:  The law applicable to maritime areas does not fade away in the face of armed conflict ; it adapts to it and superimposes itself on it. » (Daillier, Public international law, LGDJ).
This articulation was confirmed by the San Remo Manual (1994), which regulates military operations at sea while preserving freedom of navigation and the rights of third states.
In the context of the 2026 conflict, riparian states may be tempted to restrict passage through measures such as blockades, controls or threats of closure. However, these measures can never be unlimited. They must respect fundamental principles: proportionality in the use of force, the distinction between military and civilian targets, as well as the protection of the interests of third states. As Dupuy points out, “war does not constitute a space of lawlessness, but a field of reinforced legal constraints.”
Even in a military context, closing the Strait of Hormuz remains legally impossible. Alain Pellet recalls that “the closure of an international strait constitutes one of the most serious attacks on the maritime legal order”. It simultaneously violates the conventional norm (UNCLOS), the customary norm and the collective interest of the international community. The international responsibility of the State which attempted such action would then be engaged, with the obligation of cessation, reparation and guarantees.
Comparative approaches and international responsibilities
The history of international straits allows us to better understand the solidity of the legal regime. The closure of the Strait of Tiran in 1967 was considered a casus belli, triggering regional tensions, but it was never followed by legal recognition or the creation of a general rule. Daillier comments: “The Tiran episode is more about conflictual practice than normative training.”
The Bosphorus Strait, in Turkey, is another example: subject to the Montreux Convention, it allows certain restrictions in times of war, but guarantees the maintenance of commercial navigation. It illustrates that even in times of conflict, limitations must remain exceptional and regulated, confirming the primacy of freedom of transit.
In the 2026 conflict, any substantial restriction of the Hormuz crossing would engage Iran’s responsibility in accordance with the Draft Articles on State Responsibility (2001). This includes obligations to immediately cease the violation, repair damages and provide safeguards for the future. The United States, for their part, must ensure that their military operations respect the Geneva Conventions of 1949. Alain Pellet insists: “The invocation of self-defense cannot exempt from respecting the fundamental rules of humanitarian law  ” (Pellet, Responsibility in international law).
Thus, the Strait of Hormuz perfectly illustrates the tension between power logic and legal constraints. Even under military pressure, transit passage remains a fundamental norm, unsusceptible to suspension, guaranteeing that the sea remains a space of regulated freedom. As Dupuy summarizes, “the sea remains, even in times of war, a space of regulated freedom, and not a theater of arbitrariness”.
Ultimately, the current situation confirms that international law does not automatically give in to the balance of power. It adapts, reaffirms itself and maintains a protective legal framework, ensuring that the Strait of Hormuz remains an open and safe passage for international navigation, regardless of the crises and conflicts that may cross it.
Avocat international
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