Little traffic is entering and leaving Iranian ports in the Persian Gulf and the Gulf of Oman on the first full day of the US-declared blockade, according to ship-tracking data.
Shipping through the Strait of Hormuz also remains severely curtailed, with just a handful of tankers and bulk carriers transiting the waterway in the last day.
“Transit activity continues but remains constrained and uneven,” according to analysts at marine consultants Windward.
One oil tanker passed through the Strait of Hormuz in the early hours of Tuesday – the Chinese-owned vessel Rich Starry – according to MarineTraffic data.
Rich Starry is owned by Full Star Shipping Ltd, linked to Shanghai Xuanrun Shipping Co Ltd, and has been sanctioned by the United States since 2023 due to its Iran ties. It had left an anchorage off the United Arab Emirates on Monday.
Another sanctioned tanker – the Elpis – also passed through the Strait overnight but was later almost stationary in the Gulf of Oman. It’s not clear why.
The Elpis is shown as partially laden by MarineTraffic. It was sanctioned by the US in 2025 for its “involvement in the sale, purchase, and transportation of Iranian petroleum” as part of Iran’s shadow fleet – ships that use tactics such as turning off trackers to transport oil in defiance of sanctions.
Just how the US naval blockade will be enforced remains uncertain.
“Enforcement is expected to be more straightforward for outbound traffic, but more complex for inbound vessels and for those operating under deceptive conditions,” Windward said in its latest report.
“I would be careful not to interpret that too literally as a physical interdiction at the Strait itself,” Bjorn Hojgaard, CEO of Anglo-Eastern, a ship management company, said of the US action.
“Ships that have traded through the Strait may face intervention later, potentially anywhere in the world,” Hojgaard told CNN.
“Enforcing this is going to be messy,” marine consultant Erik Bethel said.
According to satellite imagery, about 20 vessels were near the Iranian coast with their transponders turned off, especially near Kharg Island and the port of Assaluyeh, Bethel told CNN Monday.
