EU drafts new sanctions targeting Moscow’s “shadow fleet,” aiming to block flag states from registering Russian vessels

The European Union is considering additional restrictions on countries providing registration to the so-called “shadow fleet” of Russian oil tankers, according to reporting by Bloomberg. EU foreign ministers will meet in Brussels on Nov. 20 to discuss the plans in greater detail.

In a document circulated ahead of the meeting and obtained by the publication, Poland proposed new rules and stronger coordination — including on complex issues such as the legal authority for boarding a vessel.

According to the document, the EU has carried out extensive diplomatic outreach to “flag states” and has been “largely successful” in convincing many of them to withdraw the registration of these vessels. Warsaw also proposed working with port and coastal states, as well as those that provide services to such ships. Any new measures would be part of the EU’s 20th sanctions package, the anonymous sources said.

Why the new measures matter — and what they won’t solve

Freedom of navigation is enshrined in international law, including the UN Convention on the Law of the Sea (UNCLOS), which forms the basis for regulation of all maritime activity. Under the convention, any vessel officially flying a state’s flag has the right to innocent passage, including through the Danish Straits and the Baltic Sea, which is divided among exclusive economic zones (EEZs) of coastal states that exercise partial sovereignty.

A ship without a flag, however, can be detained. Estonia relied on this principle when it stopped the tanker Kiwala (IMO: 9332810) in April 2025 after it sailed under a false Djibouti flag. The same vessel, renamed Boracay, was detained again on Sept. 27 by France on the same grounds.

Such detentions have been relatively rare, this despite the fact that “shadow fleet” vessels regularly and freely transit the Baltic and the Danish Straits. According to two experts who spoke to The Insider — Gonzalo Saiz Erauskin of the UK’s Royal United Services Institute (RUSI) and Pierre Thévenin, an international maritime law expert at the Stockholm International Peace Research Institute — Europe’s apparent reluctance stems mainly from weaknesses in international maritime law, which Russia actively exploits.

Authorities cannot go further than detentions, Thévenin explained, as demonstrated by the case of Kiwala/Boracay, which was released by both Estonia and France soon after being detained. Confiscating tankers is nearly impossible, even if they operate without valid documents, registrations, permits, or insurance, he said. Under UNCLOS, a vessel cannot be held for an extended period in port. If it pays a fine under the detaining state’s national law and passes the necessary technical inspections to regain sailing permission, further detention becomes unlawful, as does any attempt to hold its crew.

“If a ship that has paid a fine is kept under arrest, that could trigger a case at the International Tribunal for the Law of the Sea,” Thévenin said. “In other words, existing maritime law is insufficient to fully address the problem. Confiscation is dangerous because if the EU takes such steps, other states — China or Russia, for example — could do the same. Essentially, that would mean the end of freedom of navigation, and no one wants that.”

States themselves seek to avoid such conflicts, Erauskin explained, raising the example of the Jaguar. In May 2025, multiple ships of the Estonian Navy attempted to force that shadow fleet vessel into the country’s territorial waters. Although the Jaguar was flying the flag of Gabon, Russia sent fighter jets into the area. Russia later detained the Estonian ship Green Admire, releasing it shortly afterward. According to Erauskin, this incident illustrates why detentions are not the answer to solving the problem of the shadow fleet:

“States are not too eager to detain ships. Intercepting a vessel might escalate tensions, as seen in the Russian response to protect the Jaguar tanker. Even if a ship is detained and escorted to a port, the intervening state will then face challenging questions: who will pay for the maintenance of the ship, how long is it willing to have a tanker taking up space in its port, what happens to the cargo, what happens to the crew? This is still a contentious matter and numerous shadow fleet vessels flying false flags continue to transit without disruption.”

In theory, a vessel without a flag has no right to navigate in open seas or EEZs and may be arrested by any state’s navy or coast guard. But the key question remains: what happens after the ship’s arrest? In practice, Baltic and Scandinavian states, like other coastal nations, have very limited options.

There has been only one actual confiscation of a shadow-fleet vessel by a European country: in January 2025, Germany towed the tanker Eventin into waters near the port of Sassnitz after the oil-laden ship drifted near the island of Rügen, posing a serious environmental risk. Later, a German Finance Ministry spokesperson clarified that “customs measures had not yet been adopted in a legally binding form,” leaving the tanker’s fate unresolved. The ship was subsequently re-registered under the German flag. Its crew was replaced, and, according to Der Spiegel, the cargo was declared to be German property.

Experts interviewed by The Insider say the surge in fraudulent registrations and rapid “flag-hopping” poses an acute threat to the integrity of the system, one that could only be solved via a new convention on vessel registration by the International Maritime Organization (IMO). The IMO’s legal committee is currently reviewing the issue of fraudulent registration, but the process is extremely slow, a source familiar with the matter said.

The source added that meaningful action is likely only if a major environmental disaster caused by a shadow fleet vessel occurs off the coast of a wealthy, influential state. Most IMO regulations, he noted, are adopted only after the onset of preventable crises.