Hormuz tanker traffic plunges 60% as US-Iran truce collapses

Just 13 tankers crossed the Strait of Hormuz on Wednesday, down from an average of 33 per day over the previous week, as renewed U.S.-Iran hostilities brought the fragile reopening of the world's most important oil chokepoint to a halt, according to ship-tracking data from Kpler.

"The collapse of the ceasefire framework, the reimposition of Iranian oil sanctions, and the scale of U.S. kinetic action inside Iran represent the most significant escalation of the conflict since its opening phase," Windward, a maritime intelligence firm, told clients in a Wednesday note.

The strait handled about a fifth of global oil supplies before the war erupted Feb. 28 with U.S. and Israeli strikes against Iran. Daily traffic had rebounded to an average of 40 ships over the past two weeks after the U.S. and Iran signed a memorandum of understanding June 17 to reopen the waterway, with a peak of 59 crossings on June 24. That was still far below the pre-conflict average of 125 to 140 daily sailings. On Wednesday, only 21 commodity carriers crossed in either direction, Kpler data show, making it one of the thinnest traffic days since the interim deal.

The renewed fighting threatens to reverse the partial normalization of oil flows through the strait, where Iran had demanded ships use a northern route under its control for safe passage while attacking vessels using a U.S.-protected southern corridor along Oman's coast. Three commercial ships were hit this week, including the Marshall Islands-flagged Qatari LNG tanker Al Rekayyat, which remains stranded off Oman after a projectile strike sparked an engine room fire. Oil prices have rallied more than 6% this week as traders price in the risk of another prolonged disruption.

Iran's dual strategy of coercion and navigation interference

Iran's Revolutionary Guards Navy said Thursday that U.S. attacks on Iran and intervention in redirecting shipping were disrupting the strait's gradual reopening, warning that any further U.S. intervention would draw a "crushing response." Tehran has attacked three tankers this week using the southern corridor, part of what Windward described as "a sporadic targeted campaign by Iran to destabilize that southern corridor and send a message to Gulf State producers."

The U.S. has launched two rounds of airstrikes against Iran in retaliation, and President Donald Trump declared the ceasefire over Wednesday. Some war underwriters have advised shipping companies to pause voyages through the strait, while others are reviewing policy terms after the renewed vessel attacks, insurance industry sources told Reuters. Ship broker Clarksons said in a report that "the Hormuz reopening story looks more fragile after the latest escalation."

Vessels are increasingly switching off their AIS tracking transponders to avoid detection, making it harder to assess the true volume of traffic. Only two tankers were observed crossing the strait early Thursday — the U.S.-sanctioned Iranian supertanker Berg 1 and the Marshall Islands-flagged chemical tanker Well Sail, according to Kpler. At least nine empty supertankers with capacity exceeding 18 million barrels have been spotted anchored off Pakistan, all previously involved in ship-to-ship transfers linked to sanctioned oil.

What's at stake for global oil markets

The Strait of Hormuz handled roughly 20 million barrels per day of crude and petroleum products before the conflict — about 20% of global consumption. Iran's previous closure of the strait after the Feb. 28 airstrikes triggered the biggest supply disruption in history, dragging on for months. The June 17 interim deal had promised safe passage for 60 days without tolls, but the current escalation suggests a return to the wartime pattern of fewer than 20 daily crossings.

"The oil market is not pricing in a complete closure of the strait," said Andy Lipow, president of Lipow Oil Associates. "It appears to be pricing in a new normal where periods of conflict — perhaps we might call them missile skirmishes — occur between periods of relative calm that permit the transit of tankers." Brent crude has already risen more than 6% this week, and any further escalation that threatens the remaining traffic could push prices toward $100 per barrel, a level last tested during the initial closure in February.

This article is for informational purposes only and does not constitute investment advice.