Ship-to-ship oil transfers have increased in the Gulf of Oman as vessels seek alternative ways to move fuel while avoiding the Strait of Hormuz. TankerTrackers.com, a ship-monitoring firm, said it recorded at least 20 such transfers in the area, making it one of the busiest days for ship-to-ship, or STS, activity there.

STS transfers involve moving oil or fuel products directly from one vessel to another at sea. The method can be used to conceal a cargo’s origin, avoid sanctions, or transport goods without calling at risky ports. TankerTrackers.com said in a post on X that it had identified the movement of about 25 million barrels of crude oil, along with various refined fuel products.

The firm said the cargoes initially came from nearly every country in the region except Iran. It later identified five additional STS transfers, including one involving Iranian liquefied petroleum gas. Rising tension around the Strait of Hormuz is making the Gulf of Oman an important hub for such transfers as vessels try to reduce reliance on the strait.