Can Tehran enforce passage fees in Hormuz under international rules?

Iran may be able to squeeze Hormuz — but it can’t legally monetize it. While Tehran may be rebranding this control as paid “safe passage” — backed by the Islamic Revolutionary Guard Corps — the law of the seas draws a clear line: transit through vital straits cannot be turned into a unilateral toll regime.

The law is clear on Hormuz

Hormuz is governed by the United Nations Convention on the Law of the Sea (UNCLOS), which establishes “transit passage” through international straits. That right cannot be suspended, and in practice, it ensures uninterrupted navigation.

“That passage cannot be suspended at all,” Sotirios Lekkas, an international law lecturer at the University of Sheffield, tells EnterpriseAM.

The rules are straightforward: Article 38 of UNCLOS ensures unimpeded transit passage through international straits. Article 44 requires bordering states not to hamper that passage, while Article 26 prohibits charging foreign vessels simply for transiting, except for specific services actually rendered and applied without discrimination.

“If Iran and the United States are at war, that entitles Iran to use force against the US — but how does that allow tolls on neutral vessels?” Lekkas questions. “Under the law of the sea, that position has no […] basis and would amount to a clear violation.”

ICYMI- The US seized an Iranian cargo ship for allegedly attempting to breach its naval blockade, which President Donald Trump previously said would remain in full force until a peace agreement is signed. Tehran pledged to strike back and said it would not take part in a second round of ceasefire talks, upending Washington’s plans to kick off a fresh round of negotiations before the ceasefire expires tomorrow.

What is the workaround?

States rarely admit to breaching international law — they reinterpret it. “Any norm is subject to interpretation. No country says, ‘Yes, we are breaking international law.’ They frame their actions to appear legitimate,” Nikolaos Nikolakakis, an assistant professor at Zayed University, tells EnterpriseAM.

Iran’s interpretation hinges on its view that transit passage does not bind it. Because it hasn’t ratified UNCLOS, Tehran argues it is not obligated to follow that regime, and instead leans on “innocent passage” to justify a broader scope of control.

That opens the door to stricter measures. “Under innocent passage, Iran could impose conditions, require coordination, levy environmental fees, and restrict vessels it deems a security risk,” Nikolakakis says — especially those tied to countries it considers adversaries, such as the US and Israel.

At its core, the approach is strategic. “Hormuz is Iran’s biggest leverage — and it knows it,” Nikolakakis says. Even in Washington, some officials now recognize that military threats are unlikely to secure passage, while direct intervention would be highly risky.

The de-escalation window closed

For now, escalation appears constrained on all sides. “Currently, nobody has the political willingness to use force,” Nikolakakis highlights. GCC states pushed for Security Council backing to forcibly reopen the strait, but that effort failed to garner support from Europe, Russia, or China. Trump has also been unable to build up international backing for military action, Nikolakakis says.

When law falls behind

The gap is structural: “The law has been shaped because it works in favor of the industry, but there is no ready-made response to a crisis like,” Lekkas explains. As a result, shipping firms will try to find workarounds — finding solutions where frameworks offer little guidance.

And the consequences are immediate: The risk shifts to shipowners, insurers, and cargo interests — who must act ahead of any juridical clarity or diplomatic resolution, Lekkas says.

Illegality cuts both ways

“A blockade is a belligerent act — an act of war,” Nikolakakis says. To hold up legally, it must be declared, notified, and enforced. “Iran’s coastline is at least a thousand miles,” Nikolakakis notes — making a legally effective blockade difficult to sustain. “The American response is also unlawful, the blockade of Iranian ports — or the blockade of the strait as Trump called it — is unlawful,” he notes.