Strait of Hormuz: Why the US and Iran are sailing in very different legal waters

Summary

The Strait of Hormuz exists in the eye of the beholder. While everyone agrees that, geographically speaking, it is a strait – a narrow sea passage connecting two places that ships want to go – its political and legal status is rather more complicated. The United States and Iran both eye the strait – a choke point through which 20% of the world’s oil passes – very differently. Washington sees the Strait of Hormuz as exclusively an international waterway, whereas Tehran sees it as part of it territorial waters. It follows that Iran’s toll-charging of ships is seen by the U.S. as illegal. Similarly, U.S. President Donald Trump’s blockade of the passage is a “grave violation” of sovereignty to Iran. As an expert in the law of the sea, I know part of the problem is that the U.S. and Iran are living in two different worlds when it comes to the international laws governing the strait. Further complicating matters, both are in a different legal universe than most of the rest of the world. The law of the sea The “law of the sea” is a network of international laws, customs and agreements that set out the foundation for rights of access and control in the ocean. The framework sits apart from the laws of warfare, which are also relevant to the Persian Gulf situation. The United Nations Convention on the Law of the Sea, or UNCLOS, is a major plank of the law of the sea. Completed in 1982 and in force since 1994, it aims to create a stable set of zones and places – like international straits – where everyone agrees on who can do what. It has been ratified by 171 countries and the European Union, but not Iran or the United States. Iran has signed it but has yet to ratify; the U.S. has done neither. This means that the rules which almost every country in the world has consented to can’t serve as a basis of agreement over how the U.S. and Iran should govern their actions in the strait during the current war. The view from Iran Both Iran and the U.S. agree that under the law of the sea, the Strait of Hormuz is an international strait, but not on what kind of international strait it is. Moreover, they disagree on the relevant laws that exist, and how they apply. For Iran, the Strait of Hormuz is an international strait as set out under international law predating UNCLOS – notably the International Court of Justice’s ruling in the 1949 Corfu Channel case and the 1958 Territorial Seas Convention. These older standards state that foreign ships have a right of “innocent passage” through international straits. Put in other terms, this means that if a ship is simply passing through, without doing anything else and without harming the security of the coastal countries, it must be allowed passage. This gives Iran – and Oman, the strait’s other bordering country – power to make and enforce some rules over passage, such as rules for safety and the environment. They also have wide discretion to decide if passage is “non-innocent” and therefore not allowed. But it does not give them the right to impede innocent passage. Contrary to the older standard, however, Tehran claims the right to “suspend” passage through its half of the strait, citing the waters as its territorial sea. This is a violation of the 1958 Territorial Seas Convention that Iran relies on for legal support, which says that when a territorial sea is also an international strait, innocent passage cannot be suspended. The US interpretation For the U.S., the Strait of Hormuz is an international strait requiring “transit passage,” as per UNCLOS. Although the United States is not a member of UNCLOS, it argues that the agreement’s updated concept of an “international strait” should apply. Understanding a waterway as the newer type of “international strait,” which requires transit passage, shifts the balance against a coastal country’s control and toward free navigation. Under this standard, countries bordering straits – like Iran and Oman in the case of Hormuz – must also allow overflight and submarines below the surface. Passage must be allowed so long as it is “continuous and expeditious.” The U.S. has forcefully asserted this position at sea through regular “Freedom of Navigation” patrols through the Strait of Hormuz and other straits around the world. The patrols are a visible rejection of claims over the ocean that the U.S. deems illegal or excessive. The basic U.S. argument is supported by some leading legal scholars, such as James Kraska, a professor of international maritime law at the U.S. Naval War College, who decries the Iranian position as “lawfare” and argues that Iran must abide by the compromises made in UNCLOS. A ‘persistent objector’ But the U.S. is a global outlier here, and one of only a handful of countries – alongside the United Kingdom, France, Australia, Thailand and Papua New Guinea – which argue that “transit passage” is required by custom. Custom, in this sense, is established if a practice at sea is seen as consistent and is backed by wide agreement over its legality. If something is seen as customary law, it applies to everyone. The only way to prevent a custom from applying to you is through the “persistent objection rule,” which gives a country an exemption to newly emerging standards if it has shown itself to be consistently against it. Legal scholars are split on whether transit passage is customary law – although law of the sea specialists tend to say it is not. Tehran argues that even if transit passage were customary international law, Iran is a “persistent objector,” and therefore, the rule doesn’t apply to them. And it is true that Iran’s objection has been consistent. Both Iran and Oman argued in favor of innocent passage, and against transit passage, at the UNCLOS negotiations. Iran reaffirmed its perspective upon signing UNCLOS in 1982. Tehran argues that because transit passage is tied up in the compromises made by UNCLOS, only countries that ratify the treaty can claim the right to transit passage – and neither the U.S. nor Iran has ratified it. Navigating troubled waters The complex military situation and economic disruption are only part of the story of the Strait of Hormuz. What lies beneath is a complicated legal situation. Not only do the U.S. and Iran disagree about the legal status of the strait, but the countries that flag oil tankers – and which are therefore responsible for them – must also navigate their own commitments and perspectives under the law of the sea. Every nation wants to avoid a legal precedent that is contrary to its long-term interests. But for international law to function – to reduce conflict and enable trade – what is needed is an agreement about what rules exist, and a shared commitment to abide by them. Only that would achieve a stable post-war status for the Strait of Hormuz. How we get there, however, requires navigating some very tricky waters.

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Elizabeth MendenhallBy Elizabeth Mendenhall

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US-Iran Peace Deal Live: Iranian President to visit Pakistan on Tuesday as peace talks yield 60-day roadmap

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Advertisement US-Iran peace deal US-Iran Peace Deal Live: Iranian President to visit Pakistan on Tuesday as peace talks yield 60-day roadmap New Delhi,UPDATED: Jun 22, 2026 19:20 IST US-Iran Peace Deal News Live Updates: US-Iran diplomacy gained momentum after a marathon round of talks in Switzerland produced what mediators Pakistan and Qatar described as a roadmap for a final agreement within 60 days.

US Vice President JD Vance said Tehran had agreed to allow nuclear inspectors into the country and work on mechanisms covering frozen Iranian assets, regional ceasefires and the Strait of Hormuz. Vance said discussions on nuclear inspections could begin as early as this week, while technical teams will remain engaged even after Iran's top negotiators returned to Tehran following 18 hours of intensive negotiations.

The talks also established a communication channel to help ensure safe commercial shipping through Strait of Hormuz and a mechanism aimed at preventing renewed fighting in Lebanon between Israel and Hezbollah. Despite the diplomatic progress, tensions remained visible.

Iran had briefly closed the Strait of Hormuz over the weekend, accusing the United States of failing to uphold commitments to halt fighting in Lebanon. However, mediators said discussions were held in a constructive atmosphere and yielded encouraging progress.

Iranian President Masoud Pezeshkian is set to visit Pakistan on Tuesday in a trip expected to focus on bilateral cooperation and follow-up discussions on Islamabad's mediation efforts. Meanwhile, a fragile ceasefire in Lebanon largely held, marking the longest lull in violence in three months of conflict.

Lebanese officials reported near-total adherence to the truce despite isolated incidents, while Israeli leaders insisted any final agreement must ensure Iran cannot use future financial relief to support military activities or regional proxy groups.

Follow IndiaToday.in for the latest updates....Read More Iranian President Masoud Pezeshkian is expected to arrive in Pakistan on a one-day visit on Tuesday. (File Photo: Press TV) 2 Jun 22, 2026 19:20 IST US-Iran Deal: Iranian President to visit Pakistan Iranian President Masoud Pezeshkian will make a one-day visit to Pakistan on Tuesday, Iranian officials said.

Habib Abbasi, director-general of public relations at the presidential office, said the trip will focus on implementing previous agreements and exploring new trade opportunities. Pezeshkian is also expected to "express appreciation" for Pakistan's role in mediating between Iran and the United States, according to Tasnim news agency.

Jun 22, 2026 19:14 IST US-Iran Deal: Here's what happened so far - US Vice President JD Vance said talks with Iran made significant progress, with Tehran agreeing to allow nuclear inspectors, establish mechanisms for handling frozen assets and support efforts to manage regional ceasefires.

- Speaking after negotiations in Switzerland, Vance said discussions on nuclear inspections could begin as early as this week and confirmed that technical talks would continue in the coming days and weeks. - Iran’s senior negotiating team departed Switzerland for Tehran after 18 hours of intensive discussions, while technical experts remained behind to continue work on the Islamabad memorandum of understanding.

- Pakistan and Qatar, which mediated the talks, said Washington and Tehran agreed on a roadmap aimed at reaching a final agreement within 60 days and described the first round of negotiations as encouraging. - The two sides also agreed to establish a mechanism to help prevent clashes in Lebanon and create a communications channel to safeguard commercial shipping through the Strait of Hormuz, a vital route for global oil supplies.

- The talks followed an interim agreement reached last week and continued despite renewed tensions after President Donald Trump threatened military action against Iran and Tehran warned Washington over its rhetoric. - Iranian President Masoud Pezeshkian is scheduled to visit Pakistan on Tuesday for a one-day trip.

Iranian officials said he would discuss bilateral cooperation and express appreciation for Islamabad’s role in facilitating US-Iran diplomacy. - A ceasefire in Lebanon largely held on Monday, marking the longest period of relative calm in nearly three months of conflict between Hezbollah and Israel, although isolated incidents were still reported.

- Lebanese security officials said adherence to the ceasefire had been "almost total" since Saturday evening, despite reports of limited Israeli military activity in southern Lebanon and drone flights over Beirut. - The conflict in Lebanon has remained a major test for the interim US-Iran agreement, with Tehran previously accusing Washington of failing to ensure an end to hostilities and briefly reimposing restrictions in the Strait of Hormuz.

- Vance said progress had also been made toward reducing tensions in Lebanon, while negotiators worked to establish safeguards aimed at preventing future escalation. - Iranian Foreign Minister Abbas Araqchi said Tehran had secured waivers for oil and petrochemical exports, the release of some frozen assets and the launch of a reconstruction and development programme under the broader diplomatic framework.

- Oil prices, which surged after tensions disrupted shipping through the Strait of Hormuz, fell further after the latest round of talks, easing concerns about global supply disruptions. - Pakistani Prime Minister Shehbaz Sharif described the negotiations as constructive and said the first round of talks had concluded successfully, laying the groundwork for a broader peace agreement.

- Israeli officials signalled support for a diplomatic resolution but stressed that any final deal must ensure Iran cannot use financial relief or released assets to fund military activities or regional proxy groups.

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