After publication of this story, the Iran-backed Houthis announced they were prepared to attack American commercial and warships if the conflict between the U.S., Israel and Iran continued to escalate.
Merchant ships continue to trickle through the Strait of Hormuz as the Islamic Revolutionary Guards Corps, the sectarian branch of Iran’s military, sets up a tolled passageway in another attempt to control the vital waterway.
The past week saw the IRGC create a tollbooth, allowing Iran to decide whether it will grant safe passage to ships for a price. The passageway uses Iranian territorial waters, with ships going around Iran’s Larak Island, Jatin Dua, an anthropology professor at University of Michigan, told USNI News. Before the tollbooth, ships would sail closer to Omani waters, Raanan said.
The tollbooth is a way for Iran to exert additional control over the strait, Raanan said. Iran also used projectiles to attack ships as a way to exert its influence over the strait, USNI News previously reported. Those attacks led to a self-imposed closure of the strait as ships stopped sailing.
Between March 1 and 25, there were 142 transits through the Strait of Hormuz, according to Lloyd’s List Intelligence, a shipping analysis. In comparison, between March 1-24, 2025, there were 2,652 transits through the waterway. One container ship and zero tankers passed through the strait on March 25, according to the Joint Maritime Information Center, an information service created by the Combined Maritime Forces.
The historical average is 138 vessels in a 24-hour period.
Lloyd’s List Intelligence tracked 26 ships using this tollbooth since March 13, Raanan said. To use the tollbooth, a ship has to provide documentation, including information on the crew and ownership, according to Lloyd’s List. The IRGC then decides if it will allow passage. In some cases, there has been payment to use the alternate route.
“This is very unprecedented,” Raanan said. “This is not how things were moving prior to the war, and it’s a really disturbing development in terms of Iran exerting control over traffic through the strait.”
On Friday, Lloyd’s List tracked two Chinese ships that were denied passageway through the tollbooth route.
President Donald Trump said Thursday that Iran had “gifted” 10 ships carrying oil to the U.S. It’s unclear how many of the ships used the tollbooth route, but TankerTrackers.com reported that one of the ships – a Pakistani-flagged tanker – did use the route.
Overall, Lloyd’s List Intelligence tracked 46 dark transits in March, with ships going through the waterway without using their automatic identification system, Bridget Diakun, a senior risk and compliance analyst at Lloyd’s, said during a Thursday webinar. Both internationally sanctioned and non-sanctioned ships do dark transits to escape tracking.
The majority of transits – 68 percent – are done with AIS, she said. Two of the dark transits were by Abu Dhabi National Oil Company-owned ships.
Most traffic is headed eastbound away from the strait, Diakun said, with 101 eastbound transits compared to 41 westbound. The first westbound transit since the start of the war was a Greek ship on March 20.
Of the total transits, 24 percent were affiliated with Iran, 15 percent were Greek and 10 percent were Chinese.
Recently, about 90 percent of transits have some sort of Iranian nexus, Diakun said.
Shadow fleet ships, which use deceptive tactics to avoid identification, have accounted for more than 80 percent of transits in March, compared to around 15 percent in February, Timer Raanan, a maritime risk analyst, said during the Lloyd’s List webinar.
Strikes Against Merchant Ships Seemingly Slowed
Iranian strikes against merchant ships appeared to slow since March 13, around when the tollbooth route opened.
The last attack happened on March 19, when offshore tug Halul 50 was hit off the coast of Ras Laffan, Qatar. Three days prior there was a hit on tanker MT Gas Al Ahmadiah off the coast of Fujairah, United Arab Emirates.
The 22 ships that have been hit are:
There are at least seven known seafarer fatalities – one from Safesea Vishnu, four from Mussafah 2, one on MKD Vyom and one on Skylight. Three mariners are missing from Mayuree Naaree and a seafarer is missing from Skylight. Multiple injuries have been reported, according to the International Maritime Organization.
One of the concerns for anthropology professor Dua is the approximately 20,000 stranded seafarers, including those who had signed up for a ship that now cannot leave. The ships have been stuck for almost one month, and there are questions about how to replenish them with supplies, like food, for the crews, Dua told USNI News.
Recently, internet availability for the seafarers has diminished, adding another layer to the crisis affecting them, Dua said. The Michigan professor was able to maintain contact with seafarers aboard ships even during the Houthi campaign against commercial shipping in the Red Sea.
About 20 percent of the world’s oil flows through strait. The Brent crude oil price is at $113.39 a barrel, as of March 27, according to the U.S. Energy Information Administration. The Brent crude oil price was $71.32 on Feb. 27, the day before the U.S.-Israel against Iran started.
The Houthis Prepare to Join Iran, Focus on Red Sea
In a statement late Friday, the Houthi Armed Forces said it is prepared to attack American commercial and warships if the conflict between the U.S., Israel and Iran continued to escalate.
In the statement, the Houthis laid out three conditions for “direct military intervention,” according to Yaba, the Houthi-run media site.
The first condition is the other alliances joining Israel and the U.S. against Iran. The second is the use of the Red Sea to launch attacks on Iran or other Muslim countries by the U.S. or Israel. The third condition for the Houthis to enter the conflict would be continued escalation against Iran.
It is unclear whether the U.S. has any warships in the Red Sea following the departure of the Gerald R. Ford Carrier Strike Group. The majority of the U.S. warships in the Middle East were in the Arabian Sea and Persian Gulf, according to the most recent USNI News Fleet and Marine Tracker. To get into the Red Sea, those warships would have to cross through the Bab El-Mandeb Strait, a Houthi chokepoint.
The U.S. is considering sending more troops to the Middle East, according to The Wall Journal. It is unclear if that would trigger the Houthis to join with Iran in attacking American commercial and warships.
The Houthis have been relatively quiet since the U.S. and Israel launched their offensive on Iran. The Yemen-based group held the Red Sea hostage for approximately a year and a half in support of Palestine.
