A US-Iran memorandum of understanding signed this week commits both parties to keeping the Strait of Hormuz open and to completing a final nuclear agreement within 60 days — extendable — while granting Iran immediate sanctions relief in the form of US Treasury waivers and permission to export crude oil, according to The New York Times and ABC News, which published key MOU provisions on June 17, 2026. The agreement also extends a ceasefire — including in Lebanon — for the duration of the 60-day negotiating window, per Axios.

The Hormuz provisions may prove the most contentious thread in what follows. Iran's ambassador to Moscow was quoted in early June saying the strait would remain open but subject to transit fees set jointly by Iran and Oman, Reuters reported. Days later, Iran's MFA published a legal position arguing that the entire strait falls within the territorial waters of Iran and Oman — with no high-seas corridor — and that as a coastal state, Iran holds the right to regulate passage and charge for maritime services, per a June 9 MFA posting. A separate May 27 MFA statement elaborated that framing in the context of what Tehran describes as foreign aggression and a fundamental change of circumstances, invoking rebus sic stantibus — the doctrine that a treaty obligation can be suspended when conditions at the time of signing have radically altered.

That legal argument collides directly with UNCLOS Article 44, which prohibits coastal states from levying charges on foreign vessels exercising transit passage through international straits. Reuters noted in a May 20 investigation that under international maritime law, governments cannot charge for safe passage through a strait. Iran is not party to UNCLOS, but the transit-passage regime is broadly regarded as customary international law — a distinction Tehran has so far declined to address publicly. The European Union weighed in as early as April, calling on Iran to abandon the fee plan and warning that any pay-for-passage scheme would set a dangerous precedent for maritime routes globally, per Reuters.

The Ground Reality

The physical picture has lagged the diplomatic one by weeks. Shipping through Hormuz was at a virtual standstill as of April 9, despite a ceasefire then in effect, Reuters data showed. As of June 15–16, the world's largest tanker operator told the Financial Times that full transit resumption will still take weeks, Reuters reported. Iran's MFA has maintained consistently — including in a March 22 statement — that the strait is not closed and that traffic has not been formally restricted. The gap between that official posture and actual shipping behavior reflects the risk calculus operators make independent of government statements.

Meanwhile, Reuters documented in May that Iran has been installing checkpoint infrastructure on its Hormuz-area islands and pursuing bilateral diplomatic arrangements with regional partners, effectively building administrative architecture for the fee regime before any international legal sanction exists for it.

Reports from Asharq Al-Awsat, citing Iran's Fars News Agency, indicate Tehran added the maritime service fee clause to the US-Iran framework at a late stage of negotiations — a detail, if confirmed, that would suggest the provision was a deliberate insert rather than a settled mutual understanding.

What the 60-Day Clock Means

The MOU's 60-day window is designed to produce a final agreement on Iran's nuclear program, with the Hormuz and ceasefire provisions serving as stabilizers in the interim. But the transit-fee question does not appear to be resolved by the MOU text — it is deferred. The final deal will need to address it explicitly, or Iran's parallel legal and physical consolidation of Hormuz control will become a fait accompli negotiated around rather than through.

Roughly a fifth of global oil supply transits the strait. Tanker operators, energy traders, and re-insurance markets will be watching whether the 60-day window produces a durable legal settlement on passage rights or simply a temporary suppression of a dispute that structural incentives on the Iranian side keep alive.