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'Dark' Transits Through Strait of Hormuz Increase
More Vessels May Be Moving Through Than Tracking Data Indicates
Key Takeaways:
- Commercial traffic through the Strait of Hormuz remained thin June 9, though tankers like Kiara M likely transited with AIS signals turned off.
- Flows may be higher than tracking data shows as “dark” transits increase, with Kuwait marketing at least 4 million barrels and U.S. blockade actions disrupting routing.
- Shipping visibility remains limited as AIS disruptions persist and naval activity reshapes movements, with counts expected to change as vessels reappear beyond high-risk areas.
Commercial shipping through the Strait of Hormuz remained thin on June 9, though growing evidence of so-called dark transits suggests that more vessels are moving through the choke point than visible tracking data indicates.
The supertanker Kiara M was tracked off Sohar in the Gulf of Oman on June 9 after loading about 2 million barrels of Iraqi crude last week. The vessel likely exited the strait over the past day with its positional transponder switched off, a tactic used to avoid being targeted.
Further indications of improving flows emerged as Kuwait offered crude directly to Asian refiners for the first time since the war began. At least 4 million barrels are being marketed to buyers including refiners in China and South Korea, with the cargoes said to have already cleared the strait, though they have yet to register in tracking data.
Diplomatic momentum has also improved. President Donald Trump said the U.S. is nearing a deal with Iran that could bring the conflict to a close, though Israel has continued to express concerns over the long-term security implications of any agreement.
Visible flows remain muted for now. Apart from the Kiara M, five other commercial crossings were observed on June 8. Activity slowed on June 9, when only two crossings were visible in the waterway, according to ship-tracking data compiled by Bloomberg.
Alongside the supertanker, the June 8 outbound traffic included a bulk carrier and a containership. A China-linked fuel tanker followed on June 9, heading out of the strait.
The Strait of Hormuz, June 8–9: 8 transits tracked (2 inbound, 6 outbound).
Key signals from Windward's Maritime AI™ platform:
• Inbound vessel near Seerik, Iran (June 8): AIS linked to an OFAC-sanctioned tanker. Fraudulent flag. Dark for 3 days after outbound crossing on… pic.twitter.com/YJlaKLu1jF — Windward (@WindwardAI) June 9, 2026
The U.S. blockade of Iranian vessels in the Gulf of Oman is continuing to reshape regional shipping movements. American military officials said June 8 that 134 commercial ships had been redirected and complied, while U.S. forces disabled an empty oil tanker on June 8 after it tried to sail to an Iranian port in violation of the blockade.
Inbound commercial traffic on June 8 was limited to three Iran-linked ships. An India-linked bulker entered on June 9.
Ongoing disruptions to AIS transponder signals continue to obscure shipping activity, leading to frequent revisions in transit counts as vessels resurface beyond higher-risk areas and fresh information becomes available.
The U.S. naval presence may also be distorting the observations. 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.
Even before the U.S. 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.
