Maritime chokepoints refer to narrow passages, artificial canals, or natural straits through which more than 80% of global trade passes, used by container ships, tankers, cargo vessels, and bulk carriers. The 1982 United Nations Convention on the Law of the Sea (UNCLOS) regulates and largely guarantees the right of transit passage through straits used for international navigation. In this context, according to Articles 37 to 44 of UNCLOS, the right of continuous and expeditious passage for ships and aircraft cannot be hindered or suspended by the coastal state, even within its territorial jurisdiction.[i]It can be argued that certain elements of this regime have become part of customary international law.
However, Iran’s closure of the Strait of Hormuz following the war that began on 28 February 2026, and its subsequent demand of a USD 2 million fee per tanker for safe passage, has sparked a new debate. Article 26 of UNCLOS prohibits states from charging vessels fees solely for passage and permits charges only for specific services rendered.[ii] Iran is a signatory to the Convention but, having not ratified it, is not formally a party to it. However, the core provisions of UNCLOS relating to “transit passage” have acquired the status of customary international law. Iran, meanwhile, has argued that safe passage through the Strait of Hormuz requires a fee, classifying such “safe passage” as a “service” provided by the coastal state. This approach is generally regarded as inconsistent with international maritime law and, if implemented, is seen as carrying the risk of setting a precedent for all natural maritime chokepoints worldwide.
Iran, in the first instance, is reinterpreting, modifying, or deliberately blurring the concept of “services provided by the coastal state.” In this sense, the “safe passage” it proposes to offer in exchange for a specific fee refers to transit under the protection of Iranian naval forces. However, under international maritime law, services provided by a coastal state may include port services, pilotage, lighthouse and navigational aids, search and rescue operations, health inspections, or other peaceful forms of guidance. Accordingly, the United Kingdom and France, among other major powers, have taken steps to ensure the safety of transit passage through the Strait of Hormuz. It has been stated that, following a peace agreement with Iran, a multilateral coalition will be established to maintain security in the strait.[iii]
The US/Israel–Iran war has demonstrated the critical importance of natural maritime chokepoints worldwide, as well as the approaches adopted by coastal states. Iran’s new stance regarding the Strait of Hormuz has also made the positions of other coastal states in global chokepoints increasingly significant. In this context, Singapore—which controls the narrowest point of the Strait of Malacca—has repeatedly emphasized that Iran’s approach is not appropriate.[iv] In this regard, Singapore’s Foreign Minister Vivian Balakrishnan stated on 7 April 2026 that, under international law, passage through vital global trade routes is a right, not a privilege, thereby expressing opposition to Iran’s stance.[v]
Moreover, the Strait of Malacca is only 2 nautical miles wide at its narrowest point, whereas the Strait of Hormuz is 21 nautical miles wide. In addition, around 20% of global crude oil passes through the Strait of Hormuz, while approximately 29% passes through the Strait of Malacca. Similarly, about 11% of global maritime trade transits the Strait of Hormuz, compared to roughly 24% through the Strait of Malacca.[vi] These data indicate that the Strait of Malacca is at least as strategically important as, and in some respects even more significant than, the Strait of Hormuz. In his latest interview on 22 April 2026, Singapore’s Foreign Minister Vivian Balakrishnan stated that, in the event of a war between China and the United States in the Pacific, Singapore would remain neutral, and emphasized that the crisis in the Strait of Hormuz can be seen as merely a “dress rehearsal” in this regard.[vii] If Iran’s demands were considered legitimate and justified, Singapore could, by following its example, have reached an agreement with Malaysia and Indonesia to charge vessels transiting the Strait of Malacca a fee under the guise of a “safe passage service.” Similarly, Spain, Morocco, and Gibraltar could have pursued a comparable approach under the label of “safe passage.”
Both Iran and Oman apply the 12-nautical-mile territorial sea regime in this strait, which is 21 nautical miles wide at its narrowest point. In this context, Iran follows the principle of “innocent passage” as part of the territorial sea regime in the Strait of Hormuz. Accordingly, a coastal state may temporarily suspend such passage on grounds of security. In this sense, Iran is alleged to engage in actions that are inconsistent with the customary international law principle of transit passage applicable to international straits. The case of Iran and the Strait of Hormuz stands as one of the most striking examples of how maritime chokepoints can be transformed by states into strategic and geopolitical instruments. As this example also illustrates, straits can become tools used by coastal states to exert pressure and gain advantage over adversaries, particularly during periods of war.
Iran’s approach to the Strait of Hormuz creates a controversial area in the interpretation of international maritime law. Iran interprets the international strait primarily through the lens of its own security priorities. However, under the 1982 United Nations Convention on the Law of the Sea (UNCLOS) framework, the governing principle in international straits is “transit passage,” which does not grant the coastal state the authority to fully suspend transit. Iran’s current practices are described as relying on strategies that effectively obstruct or disrupt passage through the strait. These include laying mines, harassing vessels with fast attack craft, seizing ships, attacking or threatening attacks, and deterring tanker traffic. For these reasons, Iran’s actions are widely regarded as being inconsistent with international law.
[i] United Nations Convention on the Law of the Sea (1983). “Article 37-44”, https://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf, (Date Accessed: 22.04.2026).
[ii] United Nations Convention on the Law of the Sea (1983). “Article 26”, https://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf, (Date Accessed: 22.04.2026).
[iii] “UK to make ‘wide-ranging military contribution’ to Hormuz mission, says diplomat”, Independent, https://www.independent.co.uk/news/uk/home-news/france-donald-trump-keir-starmer-iran-government-b2960184.html, (Date Accessed: 22.04.2026).
[iv] “‘Malaysia won’t be lectured’: Singapore’s refusal to negotiate over Hormuz creates waves”, SCMP, https://www.scmp.com/week-asia/politics/article/3349464/malaysia-wont-be-lectured-singapores-refusal-negotiate-over-hormuz-creates-waves?module=top_story&pgtype=section, (Date Accessed: 22.04.2026).
[v] Ibid.
[vi] “Chokepoint Warfare: After Hormuz, Could Malacca, Gibraltar & Red Sea Be Next as Iran Teaches New Tactics?”, Eurasian Times, https://www.eurasiantimes.com/chokepoint-warfare-after-hormuz-could-malacca-gibraltar-red-sea/, (Date Accessed: 22.04.2026).
[vii] “Hormuz is just a ‘dry run’ if China and U.S. go to war in the Pacific, Singapore foreign minister warns”, CNBC, https://www.cnbc.com/2026/04/22/cnbc-converge-live-hormuz-singapore-fm-vivian-iran-war.html, (Date Accessed: 22.04.2026).
