Russia’s shadow fleet is a group of ageing oil tankers that ship Russian crude while dodging Western sanctions. After the 2022 invasion of Ukraine, the West capped the price of Russian oil and barred its tankers from insurance and ports. Moscow turned to hundreds of old vessels, often flagged in countries like Liberia and Panama, to keep exports moving. These ships switch off tracking signals, transfer oil between vessels at sea and use murky ownership chains. Ukraine has sanctioned many of them. The fleet earns Moscow billions that fund the war, critics say. The ships are also an environmental hazard, as many are old and poorly insured. A spill could devastate coastlines. This week, Ukraine reportedly struck one such tanker, the Rio, off Sochi with naval drones. The attack shows Kyiv is now targeting the fleet directly. Insurers, ports and navies are now watching the shadow fleet ever more closely.