War on Iran: What is Tehran's 'shadow fleet' really and how does it work? Submitted by Daniel Tester on Mon, 07/27/2026 - 15:15 US oil sanctions have forced the Islamic Republic to use ageing tanker vessels to sell its most valuable export to China and elsewhere The tanker Tejas, sanctioned by the US in May 2026 for carrying Iranian oil, docks at Qingdao, China, on 7 April 2026 (AFP) On Washington has reimposed its naval blockade of Iranian ports after the collapse of a planned peace deal to end the US-Israeli war on Iran. For decades, the US has tried to isolate Iran, holder of the world’s third largest proven oil reserves, from the global shipping industry with a range of sanctions.
However, the Islamic Republic has been able to maintain some revenue through a network of rickety tankers often described as its “shadow fleet”, which occupy a legal grey zone and use subterfuge to skirt the US measures. Shadow tankers, also known as “dark fleets” or “ghost fleets”, are ships that operate on the fringes of the global shipping industry to transport oil and other commodities from countries facing western sanctions. Many are ageing vessels that evade detection on marine traffic databases by turning off their mandatory tracking signals or broadcasting false locations.
Iran is not the only country involved in such operations: Russia, which is also subject to oil sanctions, likewise operates a shadow fleet. Venezuela did so until the US attack on the country earlier this year and the seizure of many of its tankers. The ships are usually registered in countries with low shipping taxes, lax regulation, opaque registries and few questions asked, thereby obscuring ownership.
Such vessels sail under what are known as “flags of convenience” belonging to, among others, Bermuda, Liberia, Panama, Malta and the Marshall Islands. The ships’ ultimate ownership can often be traced back to Iranian billionaires affiliated with the Islamic Revolutionary Guard Corps. Others are owned by businessmen from China, which is a major customer of Iranian oil.
The crews are often drawn from merchant seafarers from Iran, China and South Asia. Prior to the blockade, analysts estimated that the fleet consisted of about 400 ships, although counts vary. Vessels leave Iran, then unload the oil to another tanker at sea before the cargo reaches its ultimate destination.
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