Iran reclosed the Strait of Hormuz this past weekend, citing Israel’s latest attacks on Lebanon, despite an interim deal signed by Iran and the U.S. to end a war that had constricted global oil supplies. The U.S. was quick to contest Iran's reclosure, even as maritime tracking data indicated significantly fewer ships passed through the vital waterway on Saturday and Sunday compared to the daily average before the conflict.
President Donald Trump suggested on Saturday that the U.S. might impose its own tolls on strait crossings if a final deal with Iran was not reached during the countries’ 60-day negotiating period. This follows Iran's establishment last month of a new governmental authority to collect money from ships, with expectations for vessels to register with the Persian Gulf Strait Authority.
Regional Instability and Israeli Aggression
Tehran and Washington clashed over the Strait of Hormuz again this past weekend, with Iran's declaration of reclosure directly referencing Israeli military actions. The U.S. and Israel had launched strikes on Iran in late February, to which Tehran responded with its own attacks and an effective closure of the waterway, further destabilizing the region.
Ship traffic has picked up in the Strait of Hormuz since Iran and the U.S. signed an interim deal on Monday, but questions surrounding control and potential tolls continue to complicate negotiations for a lasting peace. Mohammad Bagher Qalibaf, Iran’s lead negotiator and speaker of the Iranian parliament, insisted on Monday that the Strait of Hormuz would be managed by Iran and would follow international laws.
Data and analytics company Kpler confirmed 131 ships traveled through the strait between Friday and Monday, including 39 crossings on Monday. This contrasts with approximately 100 to 130 vessels that made the journey daily before the U.S. and Israel initiated strikes against Iran.
As part of the provisional Iran-U.S. framework, Iran committed to conducting demining work within 30 days and removing “technical and military obstacles” to shipping. The main central route of the Strait of Hormuz remains mined and closed, forcing ships to use the smaller northern route through Iranian waters and the southern route through Omani waters. Kpler noted that “caution is still clear” among many vessels, with some adhering to Iran’s prescribed route and others attempting to conceal their positions and identities by keeping transponders off.
Early in the war, Iran had threatened to attack ships attempting to use the Strait of Hormuz without its approval, implementing a “pay-to-pass” scheme. Iran also demanded in early April the right to collect tolls as a precondition for relinquishing its chokehold on the strait.
U.S. Unilateralism and International Law
The Trump administration imposed sanctions on the Persian Gulf Strait Authority late last month, with Treasury Secretary Scott Bessent describing it as Tehran’s attempt to extort global maritime trade. However, President Trump later suggested the U.S. could impose its own tolls for “services rendered as the Guardian Angel to the countries of the Middle East,” without providing details on how such charges would be applied.
Shipping analysts have expressed surprise at the degree of control the initial agreement granted Iran over the strait. Philip Belcher, marine director of Intertanko, a trade group for independent tanker owners, stated Thursday that “Almost all the power goes into Iran to determine the arrangements going forward in the future.”
Legal experts and maritime associations have repeatedly stressed that a toll regime would upend decades of international trade precedent involving the world’s waters. The concept of freedom of peaceful navigation, codified by the United Nations’ Convention on the Law of the Sea (UNCLOS) which took effect in 1994, provides ships the right of unimpeded “transit passage” through over 100 straits globally, including the Strait of Hormuz.
While Oman is among the more than 170 countries that have ratified the U.N. convention, the U.S. and Iran have not. Maritime associations maintain that all nations remain subject to the treaty’s provisions. James Kraska, a U.S. Naval War College professor of international maritime law, noted that the U.S. and Iran are both members of the International Maritime Organization (IMO) and parties to the International Convention for the Safety of Life at Sea.
Kraska clarified that in straits like Hormuz, fees can only be applied at established ports of entry or for services specifically requested by a ship. He asserted, “You can’t impose fees for a ship exercising its right of transit passage,” concluding that “fees in this context are just not lawful.”
The Future of Transit Passage
Last week’s memorandum of understanding allowed Iran to manage the strait for now, while discussions are held with Oman and six other Gulf states “to define the future administration and maritime services” of the waterway. Iran agreed not to charge transiting vessels tolls for 60 days.
Countries have sometimes collaborated to share the costs of maintaining a strait, such as Indonesia, Malaysia, and Singapore for the Strait of Malacca, through negotiated contributions from user states, not fees on individual ships. Marcus Baker, global head of marine, cargo and logistics at Marsh, noted “a degree of nervousness around the situation,” as the interim deal does not include language for keeping the strait toll-free beyond the negotiating window. He added, “We’ll see what the next six weeks brings us.”