The Strait of Hormuz remains effectively closed to commercial shipping after the US and Iran clashed overnight near the waterway, attacking each other’s assets in the area.
US forces targeted missile and drone launch sites and other military assets in the Islamic Republic that they said were responsible for attacking three US warships transiting the strait.
The clashes risk undermining talks over a US-proposed deal to end the war, with Iran expected to send a response shortly. President Donald Trump again threatened more intense strikes if Iran refuses his terms. Tehran responded, saying on X that the continued hostile action against Iran “highlights the confusion and inability of the ruling authorities in the United States to properly understand the situation and find a reasonable solution to exit their self-created impasse.”
Tehran has tightened its grip on the waterway, requiring shipowners to submit detailed information — from vessel history to cargo value — to its Persian Gulf Strait Authority, adding to uncertainty and deterring voyages. There have been no observed outbound or inbound transits since Tuesday.
An oil products tanker, Interstellar, appeared off the coast of Pakistan on Friday morning, heading south and signaling its destination as Osaka in Japan with a June 1 arrival data. The time and position of the ship’s disappearance off Qeshm Island in the western arm of Hormuz on Tuesday suggests it crossed the Strait later that day.
Separately, a small products tanker, Zerba, that is estimated to have made the outbound transit on Sunday, appears to have been turned back by the US Navy, possibly twice, as it approached Washington’s de facto blockade line between Iran’s border with Pakistan and the shoulder of Oman.
Zerba appears to have departed Hamriya in the United Arab Emirates on April 30, before crossing the Strait of Hormuz on May 3.
Widespread AIS spoofing has clouded the picture, making independent verification of ship traffic increasingly difficult.
Tracking data currently shows no successful inbound transits since fresh hostilities erupted on Monday.
US Central Command said on X that American forces are preventing more than 70 tankers from entering or leaving Iranian ports, ships that have the capacity to transport more than 166 million barrels of oil.
The US naval presence may also be distorting the picture. Iran-linked vessels entering or leaving the Gulf could be switching off AIS signals to avoid detection, making it harder to track flows in real time. As a result, transit counts may later be revised upward when ships reappear further from high-risk waters.
Even before the US barred movement to and from Iranian ports, it was common for Iran-linked vessels to go dark when approaching Hormuz. Signals were often not restored until well into the Strait of Malacca — around 13 days’ sailing from Iran’s Kharg Island.
NOTES:
Because vessels can move without transmitting their location until they’re well away from Hormuz, automated positioning signals were compiled over a large area covering the Gulf of Oman, the Arabian Sea and the Red Sea to detect those that may have departed or entered the Persian Gulf.
When potential transits are identified, signal histories are examined to determine whether the movement appears genuine or is the result of spoofing — where electronic interference can falsify the apparent position of a ship.
Some transits may not have been detected if vessels’ transponders haven’t been switched back on. Iran-linked oil tankers often steam from the Persian Gulf without broadcasting signals until they reach the Strait of Malacca about 10 days after passing Fujairah in the UAE. Other ships may be adopting similar tactics and won’t show up on tracking screens for many days.
This tracker will be published during heightened tensions involving Iran, and aims to capture traffic for all classes of commercial shipping.
Photograph: Vessels passing through the Strait of Hormuz on April 8, 2026. Photo credit: Shadi J. H. Alassar/Anadolu/Getty Images
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