Iran’s armed forces block 30 vessels in Strait of Hormuz since August, choking global oil artery

Iran’s armed forces have blocked 30 vessels from passing through the Strait of Hormuz since August 22, escalating an enforcement campaign that has turned the world’s most important oil chokepoint into something closer to a toll road with a very aggressive operator.

The blockages are part of a broader crackdown by the Islamic Revolutionary Guard Corps Navy, which has blacklisted 45 tankers for alleged non-compliance with Iranian transit rules since August 24. Vessels that once sailed through relatively freely are now required to coordinate entry with Iranian authorities, pay transit fees, and stick to approved shipping corridors.

From highway to bottleneck

The Strait of Hormuz, a narrow waterway between Iran and Oman, typically handles a massive share of the world’s seaborne oil trade. Before the current standoff, more than 100 vessels transited the strait daily.

That number has collapsed to single digits.

On August 28 and 29, IRGC officials made their position explicit: no vessel can transit the strait without prior Iranian permission. That declaration put Iran’s stance in direct conflict with the US, which has maintained that the waterway should remain open to international navigation under maritime law.

The collapse of diplomacy

The current escalation didn’t materialize overnight. It traces back to a memorandum of understanding between the US and Iran in June 2026, which was meant to ease transit through the strait. That agreement lasted roughly a month before collapsing on July 8.

After the MoU fell apart, Iran’s enforcement posture shifted dramatically. What had been periodic inspections became systematic control. The IRGC Navy moved from monitoring to actively dictating who could and couldn’t pass.

US Central Command has responded with its own interdictions, executing dozens of operations against Iranian-linked shipping throughout the conflict. The result is a waterway where both sides are actively interfering with commercial vessels, creating a security environment that has pushed many ship operators to simply avoid the area entirely.

Some vessels have resorted to turning off their Automatic Identification Systems, the transponders that broadcast a ship’s location to other vessels and shore stations.

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