Shadow fleets of sanctions-skirting ships facing global crackdown: analysis

Dramatic social media footage of Belgian special forces boarding an oil tanker suspected to be linked to Russia in early March underscored a tidal shift in the West’s approach to the global shadow fleet, CBC analysis reveals. 

Using marine traffic data, input from experts, news reports and news releases, the analysis from CBC’s visual investigations team found that at least 14 shadow fleet vessels — ships sailing under false flags to skirt sanctions — were seized, detained or boarded by U.S., Indian and European Union authorities since December 2025.

“I don’t think we’ve ever had 14 cases in a year, much less 14 cases in the span of three months,” said David Tannenbaum, director of Blackstone Compliance Services, which provides sanctions compliance advice.

“These vessels are not safe. They’re carrying cargo that funds war of aggression or terrorism or nuclear proliferation,” he said. “The people behind these networks … are responsible for great human rights abuses.”

Most seizures related to Caribbean blockade 

The lion’s share of new seizures were related to the U.S.’s Caribbean blockade that began before it captured Venezuelan President Nicolás Maduro in early January. At least seven tankers were seized by the U.S. during its blockade.

Europe began escalating its push to seize ships from the shadow fleet, “inspired by the U.S. after their detention of these Venezuelan flagless tankers,” said Isaac Levi, Europe-Russia Policy and Energy Analysis team lead at the Centre for Research on Energy and Clean Air (CREA).

He says that in Europe, seizing ships at the current rate is “totally a new phenomenon.”

Indian authorities also seized three suspected Iranian tankers in the same period and most recently, European authorities interdicted three suspected Russian tankers. 

Shadow fleet still active

There are more than a thousand shadow fleet vessels, according to TankerTrackers, a maritime intelligence service that tracks crude oil shipments. Russia operates the largest contingent, experts say, chiefly using them to undermine international oil price cap rules by sailing under the flags of countries not under sanctions. 

Last year, CBC’s visual investigations team uncovered how shadow fleet vessels were bringing shipments of Russian oil into Canadian ports from India. 

The recent seizures represent a shift to more aggressive enforcement that​​ is “well overdue,” said Blackstone’s Tannenbaum.

“The seizures add a whole other dynamic that encourages people to conduct better due diligence in the transactions that they’re having,” he said.

The increase in enforcement has already led to shifts in the shadow fleet itself.​​ According to the International Institute for Strategic Studies, a U.K.-based think-tank, Russia has responded by reflagging vessels to official Russian registration and employing military escorts. 

Despite added pressure, the shadow fleet is still active. 

According to shipping industry trade publication Lloyd’s List, roughly half of all oil tankers and gas carriers over 10,000 deadweight tons (a shipping measurement expressed in tonnes) that moved through the Strait of Hormuz between March 1 and 8 were shadow fleet vessels. The strait is a critical chokepoint for global oil shipments controlled by Iran. 

U.S. issues waiver on Russian oil

This week, U.S. President Donald Trump issued a 30-day licence for countries to buy Russian oil currently stranded at sea to ease pressure on oil prices rocked by the U.S.-Israeli war against Iran and the blockade of the Strait of Hormuz.

The move to ease sanctions was criticized by Ukrainian President Volodymyr Zelenskyy, who said Friday that doing so could provide Russia with billions in revenue that would likely help fund its war effort.

The notion of the temporary waiver also came up in discussion among G7 leaders this week, and on Friday, Prime Minister Mark Carney said Canada would maintain sanctions on Russia “including on the shadow fleet, which is moving this oil.”

“I don’t think it’s going to move the needle on oil prices at all,” Tannebaum said of the waiver. “A lot of the dark fleet vessels were already still dropping cargo off in India.”