Iran warns commercial vessels not to use new Strait of Hormuz shipping lane

Iran's Islamic Revolutionary Guard Corps (IRGC) has warned commercial vessels that they are only permitted to use routes through the Strait of Hormuz approved by Tehran, introducing a new point of contention in fragile ongoing talks between the United States and Iran over the future of the strategic waterway.

The warning came after Oman announced a new shipping lane through the strait on Wednesday (June 25), saying it had coordinated with the IMO to establish the passage, as maritime traffic slowly recovers from weeks of disruption.

This dispute is one of several unresolved issues after the United States and Iran signed a memorandum of understanding (MoU) last week. That accord largely ended hostilities in a four-month U.S.-Israel conflict with Iran and kicked off a 60-day negotiation process aimed at a broader peace deal.

The memorandum, which includes reopening the strait, came after months of severe shipping disruptions following Iran's de facto closure of the waterway and a corresponding U.S. naval blockade of Iranian ports.

Both Washington and Tehran have declared the strait open for commercial traffic, but questions remain about whether Iran will seek tighter control over vessel movements, impose transit fees or service charges on ships using the strait after the 60-day negotiation period, and whether these disagreements over the waterway could derail efforts to reach a permanent settlement.

Strategic importance of the Strait of Hormuz

The Strait of Hormuz is one of the world's most strategically significant waterways. Approximately one-fifth of the global oil supply and liquefied natural gas (LNG) typically passes through this narrow channel connecting the Persian Gulf to the Arabian Sea.

Bordered by Iran to the north and Oman and the United Arab Emirates (UAE) to the south, the strait is roughly 50 km wide at its entrance and exit, narrowing to about 33 km at its narrowest point. Despite its limited width, the strait is deep enough to accommodate the world's largest oil tankers.

According to the U.S. Energy Information Administration, roughly 20 million barrels of oil and petroleum products passed through the strait daily in 2025, representing hundreds of billions of dollars in annual energy trade.

The route is used not only by Iran but also by Iraq, Kuwait, Qatar, Saudi Arabia and the UAE. It is also vital for global fertilizer exports, with roughly one-third of international fertilizer trade normally transiting the waterway.

Because shipping disruptions here quickly drive up global energy prices and destabilize U.S. markets, control of the waterway has become one of Iran's most powerful strategic levers in its conflict with Washington.

Why Iran opposes Oman's new route

The IRGC said Oman and the IMO announced the new shipping corridor without consulting Tehran. "Some authorities have announced a new shipping route through the Strait of Hormuz without prior notice or coordination with the Islamic Republic of Iran. The proposed route is unacceptable and poses serious safety risks," the force declared.

"The only permitted warning routes through the Strait of Hormuz are those designated by the Islamic Republic of Iran," the IRGC added, stressing that vessels must maintain contact with the IRGC Navy when transiting the waterway.

Iran first published a map of acceptable routes through the strait in April, showing that ships should travel closer to the Iranian coast than before.

The IRGC warning came after a Liberian-flagged oil tanker transited the strait on Thursday (June 26) via a route much closer to the Omani coast.

Al Jazeera correspondent Resul Serdar, reporting from Tehran, said the IRGC appeared frustrated that Oman's route partially bypasses Iran's direct control over shipping.

"Control of the Strait of Hormuz has been a huge lever for Iran to pressure its adversaries and the global economy since the start of the war," Serdar said.

Oman defended the corridor it announced, saying it aims to restore safe navigation while complying with international law. Foreign Minister Badr Albusaidi said Oman remains committed to ensuring freedom of navigation through the waterway and stressed that "future arrangements concerning the strait will not involve imposing any transit fees."

What the U.S.-Iran agreement says about the strait

In the MoU signed last week, Iran agreed that it would "make arrangements using its best efforts to ensure the safe movement of free commercial vessels, for a period of 60 days only, from the Persian Gulf to the Arabian Sea and vice versa."

While the agreement states that "the circulation of commercial vessels will begin immediately," it also acknowledges that mine-clearing operations will be required before normal shipping routes can be fully restored, noting that "the mine-clearing of the Islamic Republic of Iran will be established within 30 days." It also provides for discussions between Iran, Oman and other Gulf states on future arrangements to manage the waterway.

However, the memorandum does not specify what happens after the initial 60-day period. Ali Vaez, Iran project director at the International Crisis Group, said a temporary diversion of ships was always expected due to the mine-clearing operations outlined in the agreement.

"We always knew that if there were an agreement, there would be a few weeks of mine-clearing operations in the international shipping lane running through the middle of the Strait of Hormuz," he said. "During that period, ships would have to pass through the territorial waters of Iran and Oman as an alternative."

Nevertheless, Vaez said Iran's latest statement came as a surprise. "The important thing now is that the Iranians do not start charging fees or other taxes," he added, "because that is not stipulated in the memorandum."

Asked whether the IRGC stance differed from that of the Iranian government, Vaez said: "There is no difference between the IRGC and the state. They are essentially one. The IRGC is the one calling the shots."

Can Iran charge ships?

International law generally protects the right of transit passage through international straits, including Hormuz, making it difficult for coastal states to unilaterally impose transit fees on vessels simply passing through international shipping lanes, even if they lie within territorial waters.

Last week, Iran announced it would waive proposed transit fees through the strait for 60 days while negotiations with the United States continued in Switzerland, suggesting fees could be applied after the negotiation period ends.

Iran's lead negotiator, Mohammad Bagher Ghalibaf, signaled that Tehran sees a post-war settlement as fundamentally different from the status quo that existed before the conflict. "Hormuz will never return" to its pre-war state, Ghalibaf said.

The suggestion that Iran might charge fees was rejected by U.S. Secretary of State Marco Rubio this week. Speaking at the start of a regional tour in the UAE, he said: "It is an international waterway. No country is allowed to charge transit or fees on an international waterway." Rubio added that he believed "all the countries in this region will agree."

Speaking in Manama, Bahrain, after meeting with the Gulf Cooperation Council (GCC) on Thursday, Rubio also told reporters: "The Iranians say one thing, but then something else actually happens. It's clear to us that... the Iranian system will generate all sorts of maximum rhetoric. What we are interested in is not their press conferences. What we are interested in is whether the ships are moving. If the ships are moving as they should, that is what we will assess. On the other hand, if the rhetoric is backed up by actual ships being threatened and ships not moving, then that is a violation of the agreement and we will have a problem with it."

Rubio stated that there is no regional support for Iranian transit fees, saying: "There is no support among the Gulf states for any kind of tolls or fees being charged for the use of international waters... that is not going to happen." His comments came after UAE presidential advisor Anwar Gargash said that new "geopolitical facts" could not be imposed on Arab Gulf states as a result of what he called "treacherous aggression against them."

Are ships returning and which route are they taking?

Some commercial shipping through the strait has resumed, although traffic remains below normal levels. Before the conflict, between 120 and 140 ships typically transited the strait daily.

According to shipping analytics firm Kpler, confirmed transits rose to 70 ships on Wednesday as mine-clearing progressed and more operators began using the Omani route.

"The U.S.-Iran MoU framework and the apparent removal of the U.S. blockade appear to have supported a short-term increase in confidence, although the IRGC warnings against using the Omani route could create a new source of contention," Kpler reported.

The firm added that incomplete mine-clearing, continued travel by ships on "dark routes" and unresolved questions about inspections, sanctions and future governance mean shipping has not yet returned to pre-war conditions.

This comes as oil prices fell to their lowest since before the Iran war, with Brent crude, the global benchmark, dropping to a low of $72.24 a barrel on Thursday. However, this remains above the pre-war price of $66.

Prospects for a peace deal

The future management of the Strait of Hormuz is just one of several issues that remain to be resolved before negotiators hope to reach a comprehensive agreement within 60 days, with another major sticking point being Iran's nuclear program.

International Atomic Energy Agency (IAEA) Director General Rafael Grossi has said the agreement explicitly calls for international monitoring of Iran's nuclear activities. However, Kazem Gharibabadi, Iran's Deputy Foreign Minister for Legal and International Affairs, said that allowing inspectors access to nuclear sites damaged in the conflict will only be considered as part of a final deal.

Questions also remain about the fate of Iran's enriched uranium stockpile, the sequencing of sanctions relief and the release of Iran's frozen assets, while regional tensions continue to pose additional risks.

Israeli forces remain deployed in areas of southern Lebanon occupied during the conflict, according to a Lebanese military source, while Israeli airstrikes continue, despite the MoU explicitly calling for "a permanent end to the war on all fronts, including Lebanon."

Vaez said visible progress would be essential if the talks are to survive, noting that "both sides must see progress, whether it is greater access for UN nuclear inspectors, sanctions relief, or dealing with the issue of Iran's uranium stockpile."

He cautioned against treating the interim agreement as a series of smaller deals. "Nothing is agreed until everything is agreed," Vaez said. "They [the Iranians] are determined to reach a comprehensive agreement within 60 days. It is a very ambitious timeline, but there must be visible momentum or this process risks collapse."

Still, Vaez said both Washington and Tehran have strong economic incentives to secure a lasting peace. "The situation in the strait had become a mutually assured economic destruction," he said. "The U.S. is facing rising energy and oil prices ahead of the midterm elections... At the same time, Iran was in an economic deep hole before this conflict started. The war only made that worse. It became a lose-lose dynamic, and both sides need a way out."