Data from MarineTraffic confirms that the Iran-flagged tankers Diona, Hero II, and Sonia I sailed past the U.S. blockade line into the Arabian Sea, carrying about 3.8 million barrels of crude. Two vessels broadcast their positions from the start of the crossing, while the third activated its tracker just beyond the line. This move comes after President Trump’s promise to lift the blockade, yet U.S. naval forces retained the blockade until the final deal is signed. Analysts say the ships’ transit marks Iran’s belief that restrictions are easing and could be its first oil export in two months. The action follows a broader uptick in Iranian-linked vessels globally since the U.S. announced plans to negotiate a deal with Tehran.
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Three Iranian tankers have crossed the U.S. blockade line in the Gulf of Oman, carrying a combined 3.8 million barrels of crude oil, according to MarineTraffic data. The vessels – Diona, Hero II and Sonia I – all flagged for Iran and owned by the National Iranian Tanker Company, passed the blockade in the early hours of Wednesday, leaving the Persian Gulf for the Arabian Sea.
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The two ships broadcast their positions from the start of the crossing, while Diona only activated its location tracker just beyond the line. This is the first time these tankers have announced their journeys since March, suggesting they may be Iran’s first sea‑borne oil export in roughly two months.
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The U.S. blockade line runs from the eastern tip of Oman to the Iranian coast through the Gulf of Oman, and is part of a wider U.S. enforcement regime that includes the Indian Ocean. Although President Donald Trump announced on Sunday that the blockade would be lifted, Navy officials confirmed in the following hours that it would remain in effect until the deal with Iran is formally signed – a deadline anticipated for Friday in Switzerland.
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Analysts from Windward Maritime Intelligence see the passage as a sign that Iran believes the blockade is no longer a threat, despite U.S. statements. They note that Iranian‑linked tankers have become noticeably more active globally since the U.S. announced the deal, with two other NITC tankers, Dan and Sinopa, recently re‑appearing in the Strait of Malacca heading toward Iran.
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The U.S. has sanctioned the National Iranian Tanker Company and its vessels, citing concerns over nuclear weapons development, support for terrorist groups, and human rights violations. The blockade has reduced Iran’s crude exports to the lowest in six years, at 260,000 barrels per day in May, less than a fifth of the 2025 average of 1.67 million barrels per day, according to data from Kpler.
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While U.S. enforcement could happen outside the Gulf, earlier intercepts of Iran‑linked vessels in the Indian Ocean show a willingness to extend sanctions enforcement beyond immediate waters. The current crossing demonstrates a bold move by Iran to reclaim its shipping lanes amid a tense negotiation environment. \
