Russia’s shadow fleet flag dilemma explained
Throughout 2026, European coastal states have pushed sanctions enforcement to a new frontier: the sea.
The UK, France, Belgium and Sweden have been boarding and seizing oil tankers that help Moscow reap oil revenues. Over the summer, the bloc stepped in with EU naval missions intercepting shadow fleet tankers further from European coastlines.
Moscow has relied on the fleet of over 1,000 old, uninsured tankers registered in third countries to discreetly sell oil above the price cap and avoid sanctions imposed over Russia’s war in Ukraine.
But as EU diplomatic efforts and sanctions enforcement have strained access to convenient ship registries, Moscow is seeking to neutralize the most effective legal hook in the EU’s toolkit: false flags.
How does flag-state jurisdiction work?
International maritime law grants a flag-state — a country where the ship is registered and whose national flag it is flying — exclusive authority over the ship. In practice it means that no other country can board, inspect, detain, or divert the ship’s course other than the flag-state.
Some countries limit access to their own nationals, others have open registries.
The Law of the Sea also states that there must be a link between the ship and the flag, but in reality this requirement is often flouted, Henrik Ringbom, Environmental Law and the Law of the Sea at the Åbo Akademi University in Finland, said.
“We have ships that have never visited the country they are flagged in, nor have their owners. This has been a common practice for business purposes since the 1950s, what is called the flag of convenience, but it has not been considered illegal despite this requirement.”
Once a ship is registered, it can receive certificates and documentation which are regularly updated to remain valid: no registration means no valid certificates. But most importantly, the absence of nationality also means that there is no state to respond and back the ship in case of interceptions.
How can a ship lose nationality?
A common scenario for a ship losing nationality is when the registry expels the ship. EU diplomats persuade flag-state governments to remove sanctioned tankers, limiting the number of flags-of-convenience available to Moscow.
By deregistering sanctioned ships, states avoid secondary sanctions. As of August 2026, the EU has sanctioned over 670 ships linked to Russian oil trade; some countries still provide flags to tankers on EU and UK sanctions lists, but not those sanctioned by the U.S.
For example, Cameroon deregistered 36 shadow fleet vessels, including oil tanker Smyrtos in early June. On June 14, the British Navy seized Smyrtos in the English Channel and arrested the Indian-national captain for allegedly breaching sanctions. The tanker is still at anchor off the south coast of England.
The UK is also leading diplomatic efforts to de-flag blacklisted ships with countries such as Panama, formerly the most popular shadow fleet flag-state.
But governments can also appeal to environmental and safety concerns due to the age and poor maintenance of the shadow fleet.
Countries that are stricter with compliance will also remove ships if they no longer meet the national standards; the flags of convenience states, however, are notorious for loose regulations and poor enforcement.
Often, ships that help duck sanctions would switch registries and names at their own initiative to evade identification, a deceptive practice known as flag-hopping.
In other cases, ships are not registered at all and fly a false flag. In 2025, shadow fleet tankers commonly displayed the flag of Malawi — a landlocked country in southeastern Africa with no legitimate maritime registry.
The United Nations agency International Maritime Organization (IMO) hosts the global database (GISIS) and regularly issues alerts exposing such fraudulent or “ghost” registries.
Are EU seizures legally sound?
The EU and individual member states present boardings as sanctions enforcement. However, the tanker’s name on the sanctions list gives no legal ground to seize it.
The United Nations Convention on the Law of the Sea (UNCLOS) provides a few exemptions to exclusive flag-state authority. The exception relevant for EU boardings refers to Article 110, which allows a warship to board the merchant vessel if there are substantial grounds to believe it has no nationality, meaning it is flying a false flag, flying multiple flags or no flag at all.
Because the Law of the Sea does not provide further guidance on how to proceed, authorities can apply their national regulations for the purpose, Ringbom explained. In the case of Belgium seizing Guinea-flagged oil tanker Ethera, the authorities relied on Belgian shipping code to inspect the tanker, and found 45 violations and placed a €10 million deposit on it.
In most flag-verification boarding cases, authorities have detained stateless tankers, imposed penalties and ultimately released the ships.
The UK went further, prosecuting Smyrtos’ captain directly. In August, the Swedish Supreme Court also upheld the decision to hand over the seized tanker Caffa to Ukraine. Caffa was linked to transporting stolen Ukrainian grain and was flying a false Guinean flag; Sweden seized the tanker in March.
The UK and France together have detained six oil tankers to date. The French Navy also supported Belgium in seizing Ethera in March. Sweden has intercepted five tankers between March and May.
In July and August, the EU also authorised its navy missions Operation IRINI and Operation ATALANTA to conduct flag-verification boardings in the Mediterranean and the Indian Ocean, respectively. Six tankers have been boarded as of Sept. 9.
How is Russia changing tack?
Because the EU caps the number of maritime registries available to Russia while raising stakes for falsely flagged ships, the campaign has had a significant impact on the shadow fleet logistics.
Potential detention, loss of assets, fines and lengthy court procedures together raise risks for Russian oil business.
Many of the sanctioned ships with uncertain registries now avoid the English Channel and sail around the West coast of Ireland and Scotland instead.
Russia also began sending a warship to escort those tankers that still traverse the English Channel to scare off potential boardings.
But the EU’s assertiveness has pushed Russia to consider more long-term solutions.
No falsely flagged tankers have loaded Russian oil over July, according to maritime intelligence company Windward. “Russia no longer will risk sending a fraudulently flagged ship,” Michelle Wiese Bockmann, a maritime intelligence analyst at Windward told The Parliament.
False flags and flags of convenience seem to be more of a burden than benefit, said Ringbom.
More than 70 tankers have switched to the Russian ship registry in the last 14 months.
In June, Russia’s transport ministry also proposed legal amendments to speed up the ship registration process and simplify requirements to welcome more foreign-owned ships. The ministry said in a press release that it expects as many as 1,000 ships.
But Russia has to weigh up a number of risks.
Most of those tankers were old when purchased for shadow fleet trading, had minimal maintenance since, and were registered with flag administrations that have little adherence to basic environmental and safety rules, said Bockmann. “Having a substandard fleet is probably not something that I would imagine Russia’s maritime administration would be entirely thrilled about.”
A legal link to Moscow makes Russia directly liable for environmental damage or maritime incidents.
Does the Russian flag limit EU sanctions enforcement?
The Russian flag offers what no flag of convenience can: a diplomatic backing of a sovereign state and a layer of military protection.
“It certainly limits the capabilities that Europe has to seize these vessels,” said Gonzalo Saiz, sanctions researcher at The Royal United Services Institute. “I believe we could have done so (utilize UNCLOS Article 110 to board vessels) earlier on, perhaps also pursuing greater powers to confiscate them … That would have also taken some of these vessels off of the market.”
Europe is also exposed to significant environmental and security risks. The more shadow fleet vessels that claim a valid Russian flag, the less power the EU has to push them further away from European exclusive economic zones, where they have freedom of navigation. It exposes those environmentally sensitive zones and critical maritime infrastructures to potential oil spills or espionage associated with Russia’s shadow fleet.
On the other end, it provides a clearer sort of chain of responsibility.
“A lot of companies were providing services either because they did not know that the ship was evading sanctions, or they were choosing not to look into that deeply’’ said Saiz. With more ships claiming the Russian flag, fewer service providers would take a risk of exposing themselves to secondary sanctions.
However the EU sanctions still lag behind the U.S. (OFAC) sanctions in effectiveness.
“We’ve sanctioned hundreds of third-country individuals and entities that are supporting Russia, but there’s a long-standing tradition in the EU to stand against secondary sanctions,” Saiz said. As the EU increasingly uses the sanctions toolkit more effectively and triggers it against third-party or third-country actors, he explained, there would be greater compliance with EU sanctions. “This is something that the EU must come to grips with.”
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