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Iran Can Issue Rules for Strait of Hormuz Transit, But International Law Governs Passage

Strait of Hormuz
Strait of Hormuz
Ali Reza Tangsiri

Ali Reza Tangsiri

commander of the Islamic Revolutionary Guard Corps Navy

“Any ship that wants to pass through the Strait of Hormuz must inform us of its nationality, type of cargo, and destination in Farsi, and if it does not do this, we will definitely go after it.”


On June 23, Iran’s state-run Islamic Republic News Agency (IRNA) quoted Rear Admiral Ali Reza Tangsiri, commander of the Islamic Revolutionary Guard Corps (IRGC) Navy, as saying that vessels seeking to pass through the Strait of Hormuz must communicate with Iranian naval forces in Farsi.

Tangsiri declared:

“Any ship that wants to pass through the Strait of Hormuz must inform us of its nationality, type of cargo, and destination in Farsi, and if it does not do this, we will definitely go after it.”

That is misleading.

The Strait of Hormuz is one of the world’s strategically most important waterways. It’s a bottleneck between the Persian Gulf and the Gulf of Oman that is just 21 miles wide at its narrowest point.

International maritime laws govern the passage through the Strait of Hormuz but Iran and Oman, whose authority over the strait’s coastal territory overlaps, can impose their own regulations. However, complying with the coastal states’ local regulations is advisable, not mandatory.

The United Nations Convention on the Law of the Sea is the key maritime law that regulates international passage through the Strait of Hormuz. Its guarantees and obligations include:

  • Right of Transit Passage: all ships and aircraft, including military vessels, enjoy the right of transit passage through straits used for international navigation, such as the Strait of Hormuz. This right allows vessels to pass through the strait expeditiously and without any unjustified interference.

  • Innocent Passage: innocent passage is applicable to ships passing through the territorial sea of a coastal state, including within the Strait of Hormuz. Innocent passage refers to the continuous and expeditious passage through the territorial sea, respecting the sovereignty of the coastal state and complying with certain rules and regulations.

  • Safety and Security: vessels must follow international maritime regulations, such as adhering to relevant security protocols and complying with safety and security measures to ensure the protection of human life, the environment, and property.

  • Navigation Warnings and Information: pay attention to navigation warnings and other information provided by relevant authorities, they include updates on potential hazards, maritime security concerns, or any temporary restrictions that may affect safe passage.

  • Consultation and Cooperation: Coastal states may establish specific regulations or requirements for vessels passing through the Strait of Hormuz. Operators and owners of ships passing through the Strait of Hormuz advised complying with any specific procedures or guidelines established by these states.

According to the United Nations Convention on the Law of the Sea (UNCLOS), a country is entitled to an “exclusive economic zone” (EEZ) beyond its territorial sea, which extends to a maximum of 12 nautical miles beyond its coast.

While there are various mechanisms for resolving overlapping maritime authority claims, both Iran and Oman have demanded a complete 12-mile boundary. That means a formal agreement must be made to confer legal authority outside geographic determinations.

UNCLOS, to which Iran became a party in 1982, gives specific guidelines for jurisdiction and rights among states and individual vessels. It gives a coastal state permission to introduce navigational requirements only within its territorial waters, especially in cases where a ship’s contents may be described as hazardous. It also allows guaranteed transit to be revoked in cases where a foreign ship’s presence is determined to be “prejudicial to the peace, good order or security of the coastal State.”

UNCLOS does not give Iran the right to demand that any ship seeking to transit the Strait of Hormuz must provide a statement of nationality, type of cargo and destination in Farsi.

The concept of transit passage enshrines respect for efficiency and continuity that benefits human commerce universally. This is particularly important regarding the Strait of Hormuz, given that, as the International Crisis Group notes, “30 percent of the world’s seaborne-traded crude oil passes through the Strait of Hormuz every day ... An intentional or inadvertent incident at sea could quickly escalate into a direct military confrontation, and risk shipping through the critical energy chokepoint.”

The United States is not party to UNCLOS but does observe freedom of navigation as a global custom. In 1987, after Iran complained about an alleged violation of claimed Iranian territorial waters involving transit through the Strait of Hormuz, the U.S. replied that the “regimes of … transit passage, as reflected in the Convention, are clearly based on customary practice of long standing and reflects the balance of rights and interests among all States, regardless of whether they have signed or ratified the Convention …”

On June 8, following a meeting in Saudi Arabia between U.S. Secretary of State Antony Blinken and foreign ministers of the Gulf Cooperation Council (GCC) member states - Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates - the governments of the United States and GCC member states released a joint statement.

It stated, among other things:

“The GCC Council and the United States reiterated their commitment to freedom of navigation and maritime security in the region and their determination to counter aggressive and illegal actions at sea or elsewhere that might threaten the shipping lanes, international trade, and oil installations in the GCC states.”