European Commission President Ursula von der Leyen and Sweden's Prime Minister Ulf Kristersson address a press conference of the 77th session of the Nordic Council in Stockholm on Oct. 28, 2025. . (Jonathan Nackstrand /AFP via Getty Images)Europe's campaign to choke off Russia's ability to finance its war in Ukraine through oil revenues began with sanctions, legislation, and price caps. But as hundreds of ships helped Moscow evade those restrictions, Western governments increasingly backed those measures with aggressive maritime enforcement — deploying naval power and pirate-like tactics to disrupt the shadow fleet.As of May 2026, a Ukrainian government register has identified 1,404 vessels belonging to Russia's so-called shadow fleet. Those ships are almost always dangerously old, uninsured, and registered in third countries where there are fewer laws to follow, so-called flags of convenience.Moscow coordinates them to carry mostly oil, but also other sanctioned products like grain illegally taken from occupied territory in southern Ukraine, in a way that allows Russia to evade sanctions.After Russia launched its full-scale invasion of Ukraine in February 2022, the EU banned Russian ships from accessing the bloc's ports as early as April and introduced its first price cap on Russian oil in December 2022.Those two moves together led Moscow to seek alternative means to keep selling oil and keep the money flowing into state coffers.However, it was only in June 2024 that the EU first issued sanctions directly against the shadow fleet: 27 tankers, "part of Putin's dark fleet," read an EU press release at the time.Since then, the EU has added new ship listings in every subsequent sanctions package and quickly shifted its language from "dark fleet" to "shadow fleet," the more commonly used term for ships that aim to deceive and disregard the law.By the time the EU adopted its 21st sanctions package in July 2026, 692 ships were on the EU's list, along with a range of individuals and companies involved in servicing shadow fleet ships and enabling the deception.Those listings have been complemented by separate lists of sanctioned ships drawn up elsewhere.The U.K.'s latest sanctions package against the shadow fleet on Aug. 6 brought the total number of ships listed to 659. The U.S has sanctioned 453 vessels, while Canada and Australia have sanctioned 731 and 262, respectively.