Legal Issues And Straits of Hormuz Closure – Law of the Sea and Other International Law Issues – As the potential crisis over Iran’s closure of the Straits of Hormuz rises, so too do the experts who analyze the legal rights relating to the threats from Iran to close the vital straits.

The US has already said it will not tolerate the closure of the oil-vital Strait traffic as Iran issues its threat for the second time in two days.
Iran’s navy chief boasted that closing the Strait of Hormuz to oil traffic would be “easier than drinking a glass of water,” although US experts beg to differ.

Regardless of the military ability of Iran to deal its threat to close the Straits of Hormuz there are also legal issues that need consideration.

Consider the legal analysis from Bahman Aghai Diba, PhD International Law of the Sea who noted that any action by Iran to stop the flow of oil from Persian Gulf countries by blocking the strait Hormuz, attacking shipping lines, trying to blow up pipelines or the production and refinery facilities of the other countries in the region (such as Azerbaijan, Kazakhstan, and Turkmenistan in the Caspian Sea, or Saudi Arabia, Kuwait, Iraq, Qatar, the United Arab Emirates, Oman, Bahrain in the Persian Gulf), will be considered a serious violation of international laws and regulations for the concerned states.

It would be in practice like giving them a declaration of war. At the same time, it would be a serious challenge to the interests of the major oil importing states, especially the USA.

Iran has signed the 1982 UN Convention on the Law of the Sea, but has not ratified it. However, Iran is committed to the convention (4), and considers the transit passage as only for those who have ratified it (US has not). So in the case of these countries Iran still believes in Innocent Passage. But innocent passage in the Straits used for international navigation is different.

One of the important subjects discussed during the various sessions of the UN Third Conference on the Law of the Sea was the regime of passage from the international straits such the Hormuz strait. The 1982 convention created and approved a new notion for passing from these straits which is called “transit passage”, and it gives more rights and freedoms to the passing ships than the previous customary regime of passage from these straits.

According to the declaration that Iran has issued at the time of signing the 1982 UN Convention on the Law of the Sea ,as far as the transit passage was concerned was that the new rights were based on the contract and therefore they extended only to those who accept all commitments coming from the 1982 convention, and that it did not extend to those who are not the members. The Iranian concern in this case, contrary to the well-known idea that it was against the big naval countries, was also coming from its conflicts with the Arab neighboring countries that tried to undermine the rights of coastal states of such waterways as much as possible. The Iran-Iraq- war (1980-1988) had added fuel to this kind of thinking.

During the Third UN Conference on the law of the Sea, the issue of passage from the international straits had gained special importance because:

1. It was a matter of controversy between the countries bordering the straits and other countries especially the countries with big naval and merchant fleets.
2. The practice of 12 mile territorial sea was recognized and supported by the countries and it added seriously to the number of international straits that were less than 24 miles and therefore entirely within the territorial limits of the bordering states.
3. The previous customary regime of passage on the basis of 1958 convention of the territorial sea (Geneva Convention) was innocent passage. “Under the regime of innocent passage codified in Section III of the 1958 Geneva Convention, the rule is established that transit is innocent only “so long as it is not prejudicial to the peace, good order or security of the coastal state.” The last section of the article also requires that submarines exercising the right of innocent passage navigate on the surface, showing their flag. In Article 16 a coastal state is given the right to “take the necessary steps in its territorial sea to prevent passage which is not innocent.” This phraseology is nebulous enough as it stands; furthermore, the use of the word “prejudicial” suggests that an actual injury to peace, good order, or security need not be taking place for the passage to be deemed no longer innocent. If a reasonable chance exists that such injury may be in the offing, the coastal state would be in a strong position to decide that the passage is not innocent and exclude the vessel from its territorial waters.” (5)

The passage of the naval units from the territorial sea or in others words, extending the right of innocent passage to warships, was a controversial issue during the Third UN Conference on the Law of the Sea, and after the conclusion of the UNCLOS. The military issues were not in the agenda of the Third UN Conference on the Law of the Sea. However, during the sessions of the conference there were efforts to include subjects like the peaceful use of the oceans but they were not seriously followed. Therefore, the 1958 Convention on the territorial Sea and the 1982 UNCLOS have no clear regulations about the passage of the naval units from territorial seas. (6) Iran believes that the passage of naval ships of other states from territorial waters is dependent on prior notification and by observing innocent passage requirements. Some other countries that have the same policy are Egypt, Oman and Yemen.

Some Iranian politicians and academics have tried to argue that Iran has the right to close the Strait if the other countries ban its oil export and imports. One of them claims: “Iran believes that its likely enemies have to know that they do not possess all the chess pieces on the board. If Tehran is due to be deprived of its oil exports or faces paralyzing sanctions, the Strait of Hormuz will not be secure to tankers and ships carrying commercial goods or weapons to and from its enemies.” (7) The legal reason that Iran uses to substantiate its position is the Geneva Convention on the Territorial Sea and the Contiguous Zone (1958).

It should be noted that this argument has many problems, some of which are:

1. Even if we accept that the regulations about “transit passage” as envisaged in the 1982 Law of the Sea convention, do not apply to the countries that have not joined it (this argument is rejected by many legal experts on the basis that the transit passage as mentioned the UN 1982 Convention has turned into a part of customary law and it is obligatory for all states, Iran has signed but not ratified the 1982 convention, and according to the law of treaties, it is under the commitment to refrain from doing anything contrary to it between the signature and ratification period), and the passage of ships from straits used for international navigation is not subject to the same kind of “innocent passage” that is mentioned in the 1958 Convention about the innocent passage from the territorial sea. The littoral states of straits used for international navigation do not have the right to suspend the innocent passage in such waterways.

1. Most of the “traffic separations lines” (these are the lines usually used by the ships travelling in the area) are situated in the side of the Strait of Hormuz, which technically, i.e. according to the international law of sea, is part of Oman’s territorial waters. The Iranian forces cannot make decisions for the other part of the Strait which is technically the territorial sea of Oman.

Notes and references:

1. There are plans to establish a pipeline in the Arabian side of the Persian Gulf to bypass the Strait of Hormuz, but it is not ready, and when it is ready, it can’t replace the entire export capacity of the Arab oil exporting countries in the Persian Gulf region.
2. Also, Ayatollah Ali Khamenei, Iran’s Supreme Leader, has given a warning that Iran would disrupt the oil shipments in the Persian Gulf if the USA “makes a wrong move” in the confrontation with Iran over the nuclear program of Iran. (

Also, in 2006, the Iranian oil Minister, Kazem Vaziri-Hamaneh, claimed that Iran may use the oil weapon, if such would serve its national interests. (, dated 27 June 2006).

Also, the Iranian government spokesperson, Gholam-Hossein Elham said: “Iran would disrupt oil supplies as the last resort if it were punished over its nuclear program”. (
5. According to the article 18 of the convention on the law of treaties:
“Obligation not to defeat the object and purpose of a treaty prior to its entry into force
A State is obliged to refrain from acts which would defeat the object and purpose of a treaty when:
(a) It has signed the treaty or has exchanged instruments constituting the treaty subject to
Ratification, acceptance or approval, until it shall have made its intention clear not to become a party to the treaty; or
(b) It has expressed its consent to be bound by the treaty, pending the entry into force of the treaty and provided that such entry into force is not unduly delayed.
6. RWG De Muralt, the military aspects of the UN Law of the Sea Convention, Netherlands Law Review, 1985, Vol. XXXII.

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