Yossi Schwartz ISL (RCIT section in Israel/Occupied Palestine) 14.07.2026
Trump demands the waterway Hormuz to return to its pre-war status as a free-for-all international shipping lane. This fundamental disagreement over the strait is at the core of the renewed clashes between the U.S and Iran. In addition to the Marxist position of backing Iran in a war with imperialism, it is interesting to whom Hormuz straits belongs to by international law.
The US military’s CENTCOM in the Middle East shared a social media post on Thursday, presented as a fact check, denying that passage through Hormuz is permitted only via routes designated by Iran.
For Iran, oversight on Hormuz is essential, experts say, not just because of the potential fees that could run in the tens of billions of dollars annually, but as a means of deterrence against future attacks by the US and Israel.
The illegal armed attack against Iran by Israel and the US on February 28, 2026, prompted Iran to “close” the strait of Hormuz to international navigation. The attack against Iran clearly contravenes Art. 2(4) UN Charter. The threats against international shipping accompanying the closing of the Strait of Hormuz that facilitates the transfer of approximately one-fifth of the oil consumed globally, as well as large quantities of fertilizers, has created a dire situation to the capitalist shipping industry and to the global capitalist economy.
The strait of Hormuz is bordered by Iran and Oman and measures approximately 20¾ nm in width at its narrowest point where the territorial seas of Iran and Oman overlap. The strait is at its deepest close to the Iranian coast. It is also an extremely busy shipping corridor. It thus meets the geographical and functional criteria to be characterized as a strait used for international navigation, as per the Suez Channel Art. 37 UNCLOS international agreement signed by many states). However, whether the regime of transit passage under article 38 UNCLOS applies to the strait of Hormuz is a contentious issue especially for the current situation, since Iran, Israel and the US are not parties to the UNCLOS.
The US claims that the regime of transit passage is part of customary international law and thus it applies to the strait of Hormuz. Iran considers that the right of transit passage is not part of customary international law. Iran has consistently stated that the strait of Hormuz is not subject to the regime of innocent passage. If the regime of transit passage is not part of customary international law, as Iran posits, then Iran has the right to take the necessary steps to prevent passage that is not innocent as Iran is under attack by the US and Israel (Art. 25 (1) of UNCLOS). and even if the right of transit passage forms part of customary international law, Iran has been a persistent objector with consistent practice against the formation of the rule. Specifically, Iran had expressed its disagreement with the regime of transit passage during the negotiations of UNCLOS 3), with its interpretative declaration upon signature of UNCLOS and its 1993 Act on the Marine Areas of the Islamic Republic of Iran in the Persian Gulf and the Oman Sea which refers only to the right of innocent passage. Thus, non-parties to UNCLOS, such as the US and Israel can only invoke the customary right of non-suspendable innocent passage through the strait of Hormuz as codified in Act, but not for itself and Israel and those states that support the attack on Iran.
During the Iraq-Iran war of 1980-1988, tankers sailing through the strait of Hormuz were repeatedly attacked by both sides a situation that prompted the US to attack Iranian oil platforms.
The situation commenced in February 2026 undoubtedly constitutes an international armed conflict (IAC). In an IAC at sea the matters not governed by the relevant UNCLOS provisions are governed by the, mostly customary, law of naval warfare which is expressed by the San Remo Manual on International Law Applicable to Armed Conflicts at Sea.
According to the relevant customary rules, belligerents have the right to transit through neutral straits used for international navigation but when one of the belligerents is bordering a strait, this area may become an area of military operations where “hostile actions by naval forces may be conducted in, on or over it” (San Remo Manual Rule 10). The belligerent State may close the strait to transit by enemy vessels and respect the transit rights of neutral vessels (San Remo Manual Rule 27). Restrictions to passage might be implemented if they relate to aversion of danger and might include the exercising of visit and search rights by belligerent warships. However, total closure by means of laying mines without providing for safe corridors would be considered illegal since it would not respect the navigational rights of neutral vessels. However, this is not the case since a limited number of vessels have been permitted to exit the strait.
Iran by international law cannot impose tax on nurtural ship by only collect money for service like helping to navigate without being damaged by mines.
At the same time the US blocked of the straits is illegal and so is the renewal attacks on Iran.
The Newport Manual on the Law of Naval Warfare characteristically notes “the law of naval warfare is characterized by an element of economic warfare”.
A question of particular importance for the present case regarding other oil tankers is whether they are contributing to the enemy’s “war sustaining effort” and whether this renders them military objectives. According to the Newport Manual, State practice regarding this issue is divided. It cannot be said that any oil tanker sailing in the area irrespective of which flag it flies constitutes a valid military objective in accordance with the San Remo Manual, which expressively rejected the notion. However, if these ships assist the US and Israel, they are legitimate targets.
The majority of States do not recognize that a war-sustaining contribution to the war effort is within the definition of military objectives. According to the majority view, export products carried by neutral vessels cannot be considered military objectives and may be interfered with only by establishing a lawful blockade. Enemy merchant vessels and their cargo, however, are always subject to capture outside neutral waters for supporting the warfighting effort, regardless of whether a blockade has been established.
Merchant ships, whether enemy or neutral, may be attacked if they are sailing under an enemy convoy, escorted by warships or military aircraft (San Remo Manual Rules 60 (d) and 67 (e)). Thus, the Trump assertion that the US will “protect ships in Middle East if necessary” while providing for an operational deterrent to the armed forces in Iran may also provide a legal basis for attacking those vessels.
Beyond the rights of visit and search against neutral vessels, the belligerents might take certain actions against enemies and neutral vessels that are strictly regulated by international law.
In addition as NYT writes:
The memorandum of understanding signed by the US President with Iran granted it official status in managing the strategic trade route.
For two months, under a secret arrangement with the US Navy, commercial tankers turned off their transmitters to evade detection by Iran as they transited the dangerous Strait of Hormuz on their way to transport oil and gas to markets around the world.
The US military provided some air cover in case of an Iranian attack, while naval officers directed the vessels by radio to stay close to the Omani coast, opposite the Iranian coastline. This allowed for a gradual increase in traffic in the strait in May and June during the temporary ceasefire in the war.
However, the framework agreement that US President Donald Trump signed with Iran last month put an end to this effort in a short time amid the military escalation, due to wording in the agreement that grants Iran formal authority in the Strait and due to the ambiguity of some of its key provisions.
Trump was determined to reopen the strait and ease the pressure on the global economy. He agreed, among other things, to end the US naval blockade of Iranian ports and allow Iran to resume oil sales for 60 days in exchange for reopening the strait.
The June agreement, known as the Memorandum of Understanding, also led to the opening of additional negotiations intended to lead to a broad and sustainable peace plan.The wording in its fifth article states that Iran “will work and invest its utmost efforts to arrange the safe passage of commercial vessels” in the Strait of Hormuz.
“No one should be surprised that Iran sees this as an explicit recognition of its permanent role in controlling the Strait of Hormuz,” said Michael Ratney, a retired veteran diplomat who most recently served as the U.S. ambassador to Saudi Arabia.