The Ports and Maritime Organization in Iran’s southern province of Hormozgan said in a statement that Stena Impero left the Iranian port of Bandar Abbas at 9 a.m. local time on Friday, and started its move toward the international corridor of marine traffic in the Persian Gulf.
Hours earlier, the tanker had begun transmitting its location for the first time in weeks just outside Bandar Abbas, where it had been detained since its July 19 seizure.
The head of the Swedish shipping firm Stena Bulk that owns the tanker said it “has been a long wait” for the vessel and its crew to be released.
Company president and CEO Erik Hanell said the vessel appeared to be in good condition and “hopefully it will be on duty within a week or so,” speaking by telephone with Swedish television.
The ship tracking website MarineTraffic.com showed the Stena Impero heading south from Iran at a speed of just over 14 mph (22 kph).
Iran seized the 30,000-ton tanker on July 19 in the Strait of Hormuz when it ignored distress calls as it collided with a fishing boat on its route.
Iran’s Islamic Revolution Guards Corps (IRGC) said the ship had also used a wrong path to enter the Strait of Hormuz, the narrow mouth of the Persian Gulf through which some 20% of all international oil passes.
The seizure came after British marines illegally seized an Iranian supertanker on July 4. Authorities in Gibraltar, a British overseas territory, seized the ship carrying $130 million in crude oil on suspicion it was breaking European Union sanctions by taking the oil to Syria. Gibraltar later released the tanker, then called the Grace 1, after it claimed Iran promised the ship would not go to Syria.
However, Iran rejected the accusations and said that it had not given any assurance over the tanker to Gibraltar.
On Monday, Iranian government spokesman Ali Rabiei told journalists the Stena Impero could leave. But the ship remained outside of Bandar Abbas until Friday.
Earlier this month, Iran released seven crew members of the Stena Impero. Sixteen stayed on board.
The ship seizures come after months of heightened tensions in the Persian Gulf, sparked by US President Donald Trump’s decision over a year ago to unilaterally pull the US out of a nuclear deal with Iran. The United States has imposed sanctions that have kept Iran from selling its oil overseas.
IRNA and AP contributed to this story.