Europe is slowly strangling the fleet of ghost tankers that bankrolls Vladimir Putin's war — and Moscow is running out of places to hide it. A new report published on September 25 by the Helsinki-based Centre for Research on Energy and Clean Air (CREA) finds that the Western crackdown on Russia's "shadow fleet" has forced 107 sanctioned vessels onto Russia's own flag registry since January 2025, while the number of ships sailing under false flags has more than halved in eight months.
The shadow fleet is the financial plumbing of the invasion: every barrel it delivers helps fund the missiles falling on Ukrainian cities. Now, CREA says, the net is tightening faster than Moscow can reflag its way out of it.
How Europe closed the flag loophole
For years, shadow tankers hid behind "flags of convenience" — cheap, lightly regulated open registries that made it easy to conceal a vessel's true ownership. Under sustained pressure from sanctioning countries, those registries began shutting their doors. Barbados and Palau removed all sanctioned shadow vessels from their books, while Panama cut the number by almost two-thirds since May 2025, according to the report.
Cornered, many operators resorted to sailing under false flags — claiming registries that don't exist or using terminated registrations and faked papers. That made the ships legally stateless, which under the United Nations Convention on the Law of the Sea gives any navy grounds to seize them. France, Sweden, Belgium and the United Kingdom have boarded suspected shadow vessels in their territorial waters, and data company Windward counts 13 ships seized in the first half of 2026 alone — most recently the oil tanker MV Sun, boarded by an EU naval mission in the Mediterranean on August 30.
The result: between last October and the end of June 2026, the number of false-flagged ships in Russia's shadow fleet plunged from 101 to 45 — more than halved.
The Russian flag refuge
With the loopholes closing, Moscow opened its own registry as a last resort. Since January 2025, 107 vessels have joined the Russian flag, growing the registry by 36 percent — from 280 to 382 ships through the end of June 2026. Seventy-two of those vessels delivered €7.5 billion worth of Russian fossil fuels worldwide in that period, and 87 percent were already under sanctions when they switched flags: this is not a commercial registry, it is a sanctions-evasion lifeboat.
"The Russian flag registry has become a one-way refuge for sanctioned vessels," said Luke Wickenden, the report's lead author. "For every ship that leaves, roughly nine enter, helping protect the oil lifeline funding Russia's bloodshed in Ukraine."
Transfers peaked in December 2025, when the United States began seizing stateless ships linked to the Venezuelan oil trade — a campaign that, TradeWinds reports, culminated in the January special-forces operation that removed former president Nicolás Maduro. Russia has since imposed an age limit on new registrations, slowing the flow — but CREA warns operators could fall back on "flag-hopping," rapidly cycling between registries to stay ahead of enforcement.
Why it matters for the war
Oil money is what keeps Putin's war machine running, and the shadow fleet is how that money moves despite sanctions. Europe's enforcement push now works in tandem with Ukraine's own campaign against Russia's energy revenues: Ukrainian sea drones have repeatedly struck Russian oil ports and tankers in the Black Sea, while long-range drone strikes have hit refineries and gas facilities as far as 3,000 kilometres inside Russia.
CREA argues the West should press harder, not ease off — expanding detentions of false-flagged vessels, imposing strict fines on their operators and insurers, and building a unified EU database of legitimate flag registries shared between port authorities to close the paperwork gaps the shadow fleet exploits.
The pressure is landing as Moscow shows strain: Denmark's defence intelligence warned this week that Russia has become "increasingly willing to take risks as the security situation in Europe deteriorates." A regime forced to hide its oil fleet under its own flag or watch it get seized has a leaking war chest — and every leak makes it harder for the Kremlin to sustain a war it can no longer afford.
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