Ships pass through Hormuz in secret as US and Iran exchange tit-for-tat attacks

Published Mon, Jul 13, 2026 · 02:07 PM

A STEADY stream of ships have passed through the Strait of Hormuz in secret in recent days, while observable traffic has dwindled, following the resumption of fighting between the US and Iran.

All of the six commodity carriers that transited Hormuz on Sunday (Jul 12) did so with their transponders turned off, according to preliminary Kpler data analysed by Bloomberg News. So-called dark crossings outnumbered observable passages for the previous three days.

Tankers that exited the strait included the Very Large Crude Carrier Humanity, laden with 2 million barrels of Iranian oil and another tanker, Capetan Andreas, carrying about 500,000 barrels of Kuwaiti oil products, data analysed by Reuters showed, while three empty tankers entered the Gulf to load oil.

There were no liquefied natural gas tankers that entered the strait over the weekend that were visible on ship-tracking data.

One tanker controlled by the Abu Dhabi National Oil Co exited the strait between July 10 and July 12, Kpler data showed. The vessel is heading for Dahej port in India.

There were no ships seen passing through the strait early on Monday, according to ship-tracking data based on Automatic Identification System signals. But vessels in recent days have appeared on either side of Hormuz – in the Persian Gulf or the Gulf of Oman – after having last broadcast their locations from the other side, indicating that they transited Hormuz without turning on their transponders.

Shipowners’ preference to go dark when pushing through Hormuz comes as the US and Iran exchange tit-for-tat attacks and also offer competing narratives of who is in charge of the strait. 

Observable crossings taking the US-supported southern corridor along the Omani coast have ground to a complete halt, with the last passage via that route happening on Jul 8. That contrasts with the northern, Iran-designated safe route, which continued to see a handful of crossings through Saturday.

The spate of Iranian attacks on vessels using the Omani corridor, including on some that had turned off their transponders, appears to have discouraged traffic on that route. The other option for shipowners is to take the northern passage, but that would expose them to costs imposed by Iran, as well as the risk of penalties from the US.

Differing declarations

Secret crossings of Hormuz first became common in mid-April, when the United Arab Emirates started moving its oil out of the Persian Gulf on tankers than had gone dark. It was a move that partially explained why the oil shortage during the war was not as bad as had been anticipated in the early days of the conflict.

Iran and the US, meanwhile, made differing declarations over the weekend of Jul 11 and 12 on whether the strait was open to traffic. Teheran said that Hormuz transits would only be possible after obtaining permission from an Iranian entity, while the US Central Command stressed that there are still pathways open to ships looking to cross freely. 

Iranian forces have attacked four vessels in the past seven days, with all of those strikes happening on the north-eastern side of Oman’s Musandam peninsula. Those locations indicate the ships likely went along a US-supported crossing along the Omani coast. The Islamic Revolutionary Guard Corps said Sunday night it intercepted two vessels it viewed as endangering shipping in the strait by proceeding along an “illegal route.” BLOOMBERG, REUTERS