Shortly after the outbreak of the war with the United States and Israel, Iran took control of the Strait of Hormuz, a key artery for global oil and gas supplies.
By threatening and attacking international shipping, Iran brought maritime traffic to a virtual standstill, giving it significant leverage over its neighbors in the Persian Gulf and the global economy.
Now, the Islamic republic is formalizing its dominance over the strategic chokepoint by imposing a new transit regime. That is despite repeated warnings from the United States, which has imposed its own blockade on the strait.
Iran’s Persian Gulf Strait Authority (PGSA) -- a new body tasked with vetting and tolling vessels -- went operationally live on May 18.
In a post on X on May 20 accompanied by a map, the PGSA outlined Iran’s zone of maritime control in the Strait of Hormuz.
It said this covered the area between the line extending from "Kuh-e Mubarak in Iran to the south of Fujairah in the UAE... to the line connecting the tip of Qeshm island in Iran to Umm Al-Quwain in the UAE."
It added that "transit through this area for the purpose of passing through the Strait of Hormuz requires coordination with, and authorization from, the Persian Gulf Strait Authority."
Iran is, in effect, “converting the strait from a disrupted transit corridor into a state-administered permit and toll regime,” Windward, a maritime intelligence firm, said in a report issued on May 20.
Though the PGSA's posts on X are cited by state media, it remains unclear who runs the account, what entity oversees it, or where its offices, if any, are located -- it does not even have a website. Iran-based investigative journalist Fatemeh Karimkhan says "there is no record" of the PGSA's existence.
"It's astonishing that an unverified Twitter [X] account can control the course of news like this," she wrote on X.
'Pipe Dreams'
The move by the PGSA drew a sharp rebuke from the United Arab Emirates, which said Iran’s claimed area of control extended to UAE territorial waters.
"The regime is trying to establish a new reality born from a clear military defeat, but attempts to control the Strait of Hormuz or infringe on the UAE's maritime sovereignty are nothing but pipe dreams," Anwar Gargash, a UAE presidential adviser, posted on X on May 21.
Iran’s Islamic Revolutionary Guards Corps (IRGC) said in a statement on May 20 it had coordinated the transit of 26 vessels through the Strait of Hormuz, which connects the Persian Gulf to the open sea, in the previous 24 hours.
“Traffic through the Strait of Hormuz is being carried out with permission and in coordination with the IRGC Navy,” the Revolutionary Guards said. RFE/RL was not able to independently verify the claim.
Windward said three VLCCs, or Very Large Crude Carriers, transited outbound through the Strait of Hormuz on May 20. They included two Chinese-controlled vessels and a South Korean-flagged tanker, it said.
Two days earlier, the United States seized an Iran-linked VLCC in the Indian Ocean. It marked the third US seizure of an Iran-linked tanker since the start of the naval blockade on April 13.
“The combined picture indicates a strait that is no longer a closed corridor, but a contested and tiered access environment shaped by parallel US enforcement and Iranian administrative control,” said Windward.
'Flat-Out Illegal'
Maritime experts said Iran’s new permit and toll regime in the Strait of Hormuz is illegal.
According to the UN Convention on the Law of the Sea (UNCLOS), ships engaged in “innocent passage” through a country’s territorial waters cannot be charged a fee. But the charter, which Iran has signed but never ratified, also states that ships can be charged for “specific services” rendered.
In an interview with RFE/RL, maritime lawyer and ocean governance specialist Ian Ralby described Iran's actions as "flat-out illegal under international law."
Experts have also questioned the legality of the US naval blockade on Iranian vessels and ports, which has disrupted Tehran’s trade by sea.
Iran’s neighbors, Iraq and Pakistan, as well as India, have signed bilateral deals with Tehran, putting them outside of Iran’s tolling system. But all other countries face paying a fee, which is reportedly around $2 million per ship, in Chinese yuan or cryptocurrency.
Iran’s toll system could generate up to $3 billion per year at current levels, experts said. That figure could rise to around $8 billion annually if maritime traffic goes back to pre-war levels, when up to 140 vessels transited the strait every day.
“The operators paying PGSA tolls are predominantly Chinese-linked and UAE-managed gray and shadow fleet actors that cannot secure state-level cover. No Western-flagged operator has publicly acknowledged payment,” Windward said in its May 20 report.
Paying the fee could make shipping companies liable to US sanctions, experts said. Despite the risks, operators may be willing to do business with Iran.
“Unfortunately, the need for maritime commerce to both exit and enter the Gulf is so extreme that many are potentially willing to pay that toll,” said Ralby, who heads the maritime security nonprofit Auxilium Worldwide.
