Shadow Fleet’s Brazen Expansion Undermines Maritime Order
In 2026, the Baltic Sea countries, France, India, and others have inspected and detained more shadow-fleet vessels than in prior years. In response, Russian military vessels have begun escorting shadow vessels through the English Channel and Baltic Sea.
The shadow fleet—a large and growing group of ships that sail outside the official shipping system—has been in the news because of its role transporting sanctioned Russian oil. In March 2026, Iranian shadow vessels began attracting attention as well, as they have been able to keep sailing despite one and then two blockades amid the war in Iran.
Characteristics of Shadow Vessels
Although there is no official definition of shadow vessels—also known as the dark fleet, the ghost fleet, or the parallel fleet—they are disproportionately old and typically feature these characteristics: Transport sanctioned cargo, have opaque ownership, lack insurance of the International Group of P&I Clubs (protection and indemnity associations), are often aging, in poor condition, or both, frequently conceal their movements.
Shadow Fleet’s Growth
In some ways, it is not surprising that the shadow fleet has emerged in recent decades: It has arisen in parallel with the rules-based international system, which came into being in the decades after World War II, with the early participation of the shipping sector. When countries violated the rules-based international order and, as a result, were put under economic sanctions by other nations, they resorted to the shadow fleet for imports and exports.
South Africa used shadow vessels during the apartheid era. Countries such as Iran, Venezuela, and North Korea have relied on shadow vessels for years, even decades. These are, however, relatively small economies. When Russia turned to the shadow fleet following Western governments’ introduction of a $60 per barrel price cap on Russian oil in December 2022, the shadow fleet grew dramatically.
Consequences of Shadow Fleet’s Expansion
The large shadow fleet has come to pose a significant problem for coastal states and legally operating vessels. These risks include collisions and other accidents; spills of oil and other hazardous substances; and the threats to the maritime order itself that arise when a significant minority of ships do not uphold rules.
In the Baltic Sea, the route most commonly used by the shadow fleet, these risks have raised especially serious concerns. Shadow vessels have also damaged undersea cables, sometimes under mysterious circumstances. On Christmas Day of 2024, the Cook Islands-flagged shadow tanker Eagle S struck four data cables and one interconnector cable in the Gulf of Finland, the Baltic Sea’s eastern end.
Environmental Risks
In addition, the shadow vessels continue to pose a severe environmental risk. In a simulation of an accident in February 2026, a research center in Geesthacht, Germany, calculated how a hypothetical spill of 48,000 tons of Urals crude oil would spread over thirty days. The simulation projected devastating effects, even with such a relatively limited spill.
The tankers that carry sanctioned oil from Russia’s Baltic ports—key players in the shadow fleet—have been operating without adequate insurance coverage, making them more vulnerable to accidents and environmental disasters.
Original Article: The shadow fleet is undermining the maritime order more brazenly than ever — Atlanticcouncil