Iran has floated the idea of charging vessels for passage through the Strait of Hormuz, a narrow and strategically vital waterway linking the Gulf with the Gulf of Oman.
Why The Strait Matters
The strait is about 167 kilometres long and, at its narrowest point, consists of two 2-mile channels separated by a 2-mile buffer zone.
It remains one of the world's most important energy chokepoints: in 2024 and the first quarter of 2025, flows through Hormuz accounted for more than one-quarter of total global seaborne oil trade and about one-fifth of global oil and petroleum-product consumption, while roughly one-fifth of global LNG trade also transited the passage.
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What Law Says
The key legal framework is the UN Convention on the Law of the Sea, or UNCLOS, which entered into force in 1994. Under its Article 38, ships and aircraft enjoy the right of transit passage through international straits, and that passage "shall not be impeded". Article 44 goes further, saying states bordering straits "shall not hamper transit passage" and that there “shall be no suspension” of it.
Meanwhile, UNCLOS does allow coastal states to regulate certain matters in their territorial seas, including safety, pollution control, and customs or immigration rules. But Article 42 says those laws cannot have the practical effect of denying, hampering or impairing transit passage. That is why legal experts generally view a toll regime as highly vulnerable to challenge.
Can Iran Do It Anyway?
Roughly 170 countries and the European Union have ratified UNCLOS, while Iran and the United States have not. That creates a legal argument over whether the strait rules are binding only on treaty parties or have become customary international law.
Experts generally see UNCLOS's navigation rules as customary law, while Iran argues it has objected consistently enough to avoid being bound. The United States disputes Iran's authority to impose tolls. That is why the legality of any toll would likely be contested immediately, even before the question of enforcement arose.
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What Happens Next
Even if Iran goes ahead with the plan, the greater issue is enforceability. UNCLOS does not provide a direct enforcement mechanism, and any dispute would likely be handled through diplomacy, shipping rerouting, sanctions pressure, or multilateral maritime coordination. The Strait's significance is amplified by the limited alternatives available: Saudi Arabia and the UAE do have some bypass capacity, but it is far from enough to replace Hormuz at full scale.
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