renewed U.S.-Iran conflict chokes Hormuz

Vessel traffic through the Strait of Hormuz has slumped since U.S. President Donald Trump’s blockade took effect last week, with shipowners increasingly avoiding one of the world’s most important energy corridors as fighting between the U.S. and Iran intensifies. 

Crossings through the Strait have fallen sharply across multiple shipping datasets with renewed U.S. strikes on Iran, Tehran’s declaration of a blanket ban on maritime traffic and fresh attacks on commercial vessels has prompted operators to reassess the risks of entering the Gulf. 

Lloyd’s List Intelligence recorded just 53 vessel transits in the week through July 20, down 66% from 157 the previous week. Tanker and gas carrier movements, which are the ships responsible for transporting most Gulf crude oil and liquefied natural gas, dropped to 30 crossings from 90. 

Kpler data similarly show activity deteriorating almost immediately after the blockade began. Daily crossings, which had averaged more than 20 vessels before July 15, fell to 16 that day before dropping to single digits on July 16. Traffic remained subdued through the rest of the week, with only sporadic recoveries.

The latest slowdown reverses weeks of gradual normalization after the mid-June ceasefire had encouraged some shipowners to resume Gulf voyages. 

Instead, the renewed fighting has once again nearly emptied the strategic waterway that carries roughly a fifth of global oil consumption. 

“Things have slowed down significantly since tensions reignited,” said Bridget Diakun, senior risk and compliance analyst at Lloyd’s List Intelligence. “That’s not surprising – people pull back and reassess, as you’d expect.” 

Traffic has not disappeared altogether, however. “Every single person has a different risk appetite,” Diakun said. “We’re still seeing tankers crossing in and out, it hasn’t ground to a complete halt.”

Rather than recovering steadily, vessel movements are likely to continue coming “in ebbs and flows” as shipowners seize brief windows of perceived safety before pulling back again whenever tensions escalate, she said.

S&P Global data painted a similar picture. Just 40 vessels transited the strait between July 17 and July 19, averaging roughly 13 crossings a day, while weekly traffic through July 19 fell almost 50% from the previous week.

Commercial ships still accounted for more than 70% of traffic over the period, although only about one-third were assessed as compliant with maritime restrictions. Iran-linked and sanctioned vessels continued to dominate many movements, suggesting mainstream international shipowners remain reluctant to return.

“The latest escalation shows how expectations of a rapid opening of the Strait were premature,” said Saul Kavonic, head of energy research at MST Marquee.

“The hostilities and reimposed blockade set the conflict back on an escalatory trajectory,” he said, adding that flows through Hormuz had dropped to around 15% of pre-war levels. Oil could retest $100 a barrel if the current intensity of fighting persists for several weeks or if regional energy infrastructure comes under attack, he told CNBC via email.