Three Iranian tankers carrying a combined 3.8 million barrels of crude oil have slipped past the U.S. blockade line in the Gulf of Oman, according to MarineTraffic data. The vessels—Diona, Hero II and Sonia I—were all owned by the National Iranian Tanker Company, which and its ships have been under U.S. Treasury sanctions.
Hero II and Sonia I left Iran’s Chabahar port on Tuesday and crossed the blockade line into the Arabian Sea in the early hours of Wednesday. Diona, which began broadcasting its position just past the line, followed suit later that day.
President Donald Trump’s promise of an immediate “removal” of the blockade was reportedly overruled by naval authorities, who confirmed that the restrictions would remain in place until a deal with Iran is finalized in Switzerland on Friday.
“We’re seeing a clear sign that Iran believes the blockade will not be renewed even if the U.S. says it will remain,” said Michelle Wiese Bockman, senior analyst at Windward Maritime Intelligence.
The U.S. blockade has historically cut Iran’s crude exports to a record low of 260,000 barrels per day in May—less than a fifth of the 2025 benchmark of 1.67 million barrels per day, according to Kpler data. As of now the three ships have yet to broadcast planned destinations, leaving their end‑points uncertain.
In light of the recent announcement of a U.S.–Iran deal, UANI reports a noticeable uptick in activity among Iranian‑linked tankers globally. Two other NITC tankers, Dan and Sinopa, have started broadcasting positions in the Strait of Malacca after a long absence.
These movements suggest that Iran is not waiting for formal diplomatic concessions and is quickly mobilising its shipping assets in the international arena.
