Three Iranian tankers—Diona, Hero II and Sonia I—have floated past the U.S. blockade line between Iran’s Chabahar port and Oman’s coast, ship‑tracking data shows. The vessels, all owned by the National Iranian Tanker Company, carried a combined 3.8 million barrels of crude oil and have not broadcast positions since March.
Hero II and Sonia I departed Chabahar Tuesday morning, crossed the blockade line before dawn, and entered the Arabian Sea. Diona began transmitting its location just after it crossed the line, while other Iranian tankers are already circling the Pakistani port of Karachi.
Every U.S. sanction continues to target Iran’s shipping industry. The National Iranian Tanker Company and its vessels, including the three that breached the line, have been subjected to U.S. Treasury sanctions for providing financial support to groups the U.S. labels terrorist and for alleged human‑rights violations.
The blockade, put in place after the Iranian revolution and intensified in 2018, has reduced Iran’s oil exports to a record low of 260,000 barrels per day in May—less than a fifth of the 2025 average of 1.67 million barrels per day. The U.S. declared it would remain in effect until a deal is signed in Switzerland this week.
Experts say the breach indicates Iran’s confidence that enforcement has eased, even as the U.S. keeps the blockade active. “This is a sign that Iran believes the blockade is over, even if the U.S. insists that it will remain in place until Friday,” said Michelle Wiese Bockman, senior analyst at Windward Maritime Intelligence.
Additional Iranian‑linked tankers have resurged worldwide, with two new crude oil vessels—Dan and Sinopa—now active in the Strait of Malacca, and an unladen tanker, Stream, heading toward Iran after stopping near Karachi.
