Arrr these inspections legal? Putin claims E.U. detentions of Russian ‘shadow fleet’ ships are ‘piracy.’ But what does the law say?

In April 2025, Estonia detained the Kivala, a tanker linked to Russia’s so-called shadow fleet. On September 27, the same vessel — now renamed the Boracay — was intercepted by French authorities.

Speaking at Russia’s annual Valdai Discussion Club Forum in Sochi the following week, Russian President Vladimir Putin denounced France’s actions as “piracy,” claiming the seizure occurred in international waters.

For insight into the legal grounds for detaining shadow fleet tankers under international law, Meduza turned to Pierre Thevenin, an expert in international maritime law and researcher at the Stockholm International Peace Research Institute.

The “shadow fleet” refers to a group of aging oil tankers registered in foreign, often developing, countries and sailing under their flags. Russia uses these vessels to evade European sanctions on its oil exports, transporting crude through Baltic ports to markets around the world.

The view from the Baltic

Surveilling Putin’s ‘shadow fleet’ Meduza’s dispatch from the Baltic Sea, where a new NATO mission aims to protect undersea infrastructure as tensions rise with Russia

6 months ago

The view from the Baltic

Surveilling Putin’s ‘shadow fleet’ Meduza’s dispatch from the Baltic Sea, where a new NATO mission aims to protect undersea infrastructure as tensions rise with Russia

6 months ago

From the European Union’s perspective, the shadow fleet poses two key concerns.

First, politically, the fleet is viewed as a deliberate attempt by Moscow to bypass international sanctions, which the E.U. considers unacceptable.

Second, there are serious environmental risks. The vessels are typically 25–30 years old and operate under flags of countries that do not enforce international safety or environmental standards. As a result, these tankers may not undergo proper technical inspections, raising concerns about their seaworthiness and structural integrity.

Compounding the risk, many of these tankers operate without insurance and routinely disable their Automatic Identification System (AIS), making them invisible to radar and significantly increasing the risk of maritime collisions.

Not exactly. Under the United Nations Convention on the Law of the Sea (UNCLOS) — the primary international legal framework governing maritime activity — a ship’s rights depend on which maritime zone it’s in. The closer a vessel is to a coastal state’s territory, the more limited its rights.

Legally speaking, there’s no such thing as “neutral waters.” Putin was likely referring to France’s Exclusive Economic Zone (EEZ), as the Boracay was reportedly in that zone when it was detained.

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Yes — to an extent. Articles 58(2) and 87 of UNCLOS guarantee freedom of navigation within countries’ EEZs. Generally, coastal states like France or Estonia cannot restrict this right, let alone detain foreign vessels.

However, this freedom is not absolute. UNCLOS includes exceptions that allow coastal states to detain foreign-flagged ships under certain conditions.

Two exceptions are especially relevant to the shadow fleet.

First, if a vessel changes its flag while at sea, it loses its nationality under UNCLOS. A ship without nationality may legally be detained by any coastal state.

In April, Estonia cited this exact legal basis when it detained the tanker then known as Kivala and escorted it to port. Judging by available reports, France appears to have used the same justification in detaining the Boracay.

The second exception relates to the authority of coastal states within their Exclusive Economic Zone. Under Article 56(1) (b) (iii) of UNCLOS, a coastal state has jurisdiction to protect the marine environment. That means it can adopt environmental laws that foreign vessels are required to follow while in its EEZ.

In March 2025, the E.U. updated its regulations accordingly. Under the new rules, any foreign vessel entering an E.U. member state’s EEZ must carry an insurance certificate recognized by the E.U. Ships without such coverage are considered in violation of environmental protection laws and are not allowed to operate in European EEZs.

This presents a significant challenge for shadow fleet tankers, which are typically uninsured and unable to obtain coverage from E.U.-recognized providers due to sanctions.

Ship nationality is checked through international maritime databases and information exchanges between coastal states.

UNCLOS Article 100 also gives coastal states the right to board and inspect vessels within their EEZ if there is reason to suspect a breach of nationality requirements or environmental regulations. These inspections are usually carried out by naval or law enforcement authorities.

If a vessel refuses inspection, authorities are permitted to board by force — though the use of force must be proportional and kept to a minimum.

If the ship attempts to flee, the coastal state has the right to initiate what’s known as a “hot pursuit.”

When a ship violates maritime rules, the typical consequence is a fine. Under UNCLOS, detained vessels cannot be held in port indefinitely. Once the fine is paid (in this case, under French law) and the vessel passes the technical inspections needed to confirm seaworthiness, there’s no legal basis for further detention.

That’s why the Boracay was released within a few days — just as it was after its earlier detention in Estonia, when it was still operating under the name Kivala.

Most likely, this restriction exists for economic reasons. UNCLOS discourages prolonged detention of commercial vessels because over 80 percent of global trade depends on the uninterrupted movement of ships between ports. Allowing countries to hold vessels indefinitely would undermine the predictability and efficiency of international shipping — a system built on timeliness and reliability.