Hormuz, Iran cannot impose the toll but it will: here is Tehran’s plan

ByEditor

Jun 16, 2026

Hormuz, Iran cannot impose the toll but it will: here is Tehran’s plan

In the debate on the Strait of Hormuz and the possible introduction of forms of payment linked to the transit of ships, the border between legitimate maritime services and a real tax on passage remains the legally decisive point. This is clarified by the Professor Marco Roscini, professor at Westminster Law School. “From the point of view of international law, it is necessary to distinguish between what can be agreed between the United States and Iran and what remains governed by international rules that are also binding on other states”, explains Roscini to Adnkronos, recalling that Hormuz “is a strait used for international navigation” and, based on the United Nations Convention on the Law of the Sea (Unclos), “is subject to the regime of transit passage, which guarantees ships and aircraft of all States the right to pass through the strait continuously and expeditiously”.

“This means that Iran cannot, in principle, arbitrarily suspend transitdiscriminate between ships on the basis of nationality, make passage subject to prior authorization or tolls, and in general impose restrictions that empty the right of passage in transit of its content”, says Roscini. Even if Tehran is not part of UNCLOS, he adds, “much of the regulation relating to international straits is considered an expression of customary international law and therefore also binding for non-party states”.

According to the professor, a possible bilateral agreement between Washington and Tehran could not change the legal regime of the Strait: “The agreement can certainly reduce military risk, provide security mechanisms, establish naval coordination or mine clearance procedures, but it cannot eliminate or restrict navigation rights belonging to third States without their consent.”

As for the topic of “maritime services”indicated by the Iranian media among the points of the memorandum, Roscini underlines that “International law of the sea normally allows a coastal state to request payment for certain servicessuch as pilotage, towing, navigation assistance and the like”. However, the case of a fee imposed for the simple crossing of the strait is different. “What the coastal State cannot do, however, is impose a tax simply for the fact that a ship exercises its right of passage in transit through an international strait”.

The distinction, he observes, is fundamental. “If the tariff remunerates a real, optional and proportionate service, it may be compatible with international law. If the fee is actually a condition for transit, regardless of the use of specific services, then it looks very much like a disguised toll and risks being incompatible with the transit regime. If such payments were mandatory to cross Hormuz, it would be difficult to distinguish them from an actual toll.”

Finally, for Roscini there is also a broader question. “From a systemic point of view, the biggest problem is the precedent that would be created. If the possibility of imposing generalized tariffs for crossing Hormuz were accepted, other states could claim similar rights in other strategic straits. This would call into question one of the fundamental principles of contemporary law of the sea, namely the freedom of navigation through the main chokepoints of world trade.”