Three Iranian oil tankers, Diona, Hero II, and Sonia I, have reportedly navigated past a US naval blockade line in the Gulf of Oman, according to analysis of ship-tracking data. The vessels, all owned by the US-sanctioned National Iranian Tanker Company (NITC), are believed to be carrying a combined total of 3.8 million barrels of crude oil. This development emerges despite an earlier announcement by President Donald Trump about the "immediate removal" of the blockade, with US naval forces subsequently clarifying that it would remain in place until a deal with Iran is formally signed in Switzerland on Friday.
The move is being interpreted by some maritime intelligence experts as a sign of Iran's confidence that the blockade is effectively over, even if the US maintains its official stance until the deal is sealed. Data from MarineTraffic indicates that Hero II and Sonia I departed Iran's Chabahar port on Tuesday, crossing into the Arabian Sea in the early hours of Wednesday. Diona, the third tanker, reportedly began broadcasting its location just beyond the blockade line, which extends from the eastern tip of Oman to the Iranian coast, on Tuesday.
This marks a significant moment, as maritime intelligence firm Windward notes it is the first time any of these specific Iranian tankers have publicly broadcast their locations since March. If these vessels successfully reach their destinations, it would represent Iran's first oil exports in two months, according to TankerTrackers.com. The US blockade had severely curtailed Iran's crude exports, reducing them to a six-year low of 260,000 barrels per day in May, a stark contrast to the 2025 average of 1.67 million barrels per day, as reported by Kpler.
The broader context for this situation lies in long-standing US sanctions against Iran, imposed over concerns about its nuclear programme, alleged support for designated terrorist organisations, and human rights abuses. The US had previously demonstrated its commitment to enforcing these sanctions, with American forces intercepting Iran-linked vessels in the Indian Ocean, thousands of miles from the Gulf region. However, since the announcement of the US deal with Iran, there has been a noticeable increase in activity among Iranian-linked tankers and cargo ships globally, according to the campaign group United Against Nuclear Iran (UANI).
In addition to the three tankers breaching the blockade, two other crude oil tankers owned by NITC, Dan and Sinopa, also began broadcasting their positions in the Strait of Malacca between Malaysia and Indonesia on Tuesday. These vessels had not been visible on public tracking platforms since early April and now appear to be sailing towards Iran. This concerted activity suggests Iran is moving swiftly to re-engage its shipping fleet and resume oil exports following the easing of tensions.