Shadow Fleet at Sea: Europe’s Battle Against Illicit Oil Shipping

Published: 19 November 2025 Wednesday . The English Chronicle Desk. The English Chronicle Online

In the western Baltic Sea, a Swedish coastguard officer’s voice crackles over the radio, attempting to hail a nearby oil tanker suspected of violating international sanctions.

“Swedish Coastguard calling… Do you consent to answer a few questions for us? Over.”

The response is slow, distorted by static. A crew member gradually rattles off the ship’s insurance information, flag state, and last port of call – Suez, Egypt.

“I think this ship will go up to Russia and get oil,” says Jonatan Tholin, a Swedish maritime investigator.

It is a scene that captures the tense, shadowy reality of Europe’s standoff with Russia’s so-called “shadow fleet.” These fleets – hundreds of tankers often operating under obscure ownership, outdated safety measures, or false flags – have become a central concern for European authorities trying to enforce sanctions against Moscow’s oil exports following the Kremlin’s full-scale invasion of Ukraine.

The “shadow fleet” is a network of vessels that deliberately bypasses sanctions, often trading Russian crude at a discount or shipping it through intermediaries to disguise its origin. Many of these ships are old, sometimes described by analysts as “floating rust buckets,” lacking proper insurance and often falsifying their registration.

Some vessels are suspected of more than just illicit shipping. Experts warn that undersea sabotage, illicit drone launches, and manipulation of Automatic Identification System (AIS) tracking signals – a tactic known as “spoofing” – have become increasingly common, further complicating enforcement efforts.

“The seas operate under freedom of navigation, which is a golden rule,” Tholin explains. “That means our ability to intervene is limited, even as the risks keep increasing.”

A growing number of “shadow” ships are sailing without a valid national flag, a practice that renders them effectively stateless. This has serious legal and financial implications: without a flag, a vessel cannot be held accountable under international maritime law, leaving insurers, regulators, and governments with limited recourse in case of accidents.

“If there’s a billion-dollar oil spill, good luck with trying to find somebody responsible to pick up any cost,” warns Michelle Wiese Bockmann, a senior maritime intelligence analyst at Windward AI.

The scale of the problem is increasing rapidly. Driven by record sanctions and tighter enforcement, the number of falsely flagged ships worldwide has more than doubled in the past year, reaching over 450 vessels, most of them oil tankers, according to the International Maritime Organization (IMO) database.

The BBC has been tracking one ship that appears to have sailed without a valid flag, highlighting the growing difficulty in monitoring and enforcing compliance in international waters. Analysts note that these vessels often switch identities, change flags mid-voyage, or anchor off coastlines for days to evade satellite tracking, making it nearly impossible for authorities to maintain oversight.

European coastal states are caught in a difficult position. Their enforcement capabilities are constrained by international law, which protects stateless vessels to some degree. Interventions must be carefully calibrated to avoid accusations of unlawful seizure or aggression, yet authorities are increasingly concerned about the potential for accidents or environmental disasters.

The potential risks of this shadow fleet extend beyond legal and financial concerns. These vessels often lack modern safety standards, leaving crews vulnerable and increasing the chance of catastrophic oil spills. In the event of a maritime disaster, the lack of a responsible owner or insurer could turn an oil spill into an environmental and humanitarian crisis.

Analysts have also raised concerns about potential military uses of the fleet. In some cases, ships have been equipped with drone launch capabilities or other technologies that could threaten naval or commercial operations in key maritime chokepoints. While such scenarios remain largely speculative, they contribute to the growing sense of urgency among European maritime authorities.

The shadow fleet has emerged as a sophisticated workaround for Russia’s energy exports. By using a network of intermediaries, false flags, and complex logistics, Moscow continues to move significant volumes of oil despite Western sanctions. Tankers sometimes transfer cargo at sea to other vessels, further obfuscating the origin of the oil and making enforcement even more challenging.

European authorities are taking a multi-pronged approach to tackle the threat. Satellite tracking and intelligence sharing among EU member states have increased, while the EU has also pressured insurance companies and port authorities to enforce compliance. However, the shadow fleet’s adaptability means that enforcement remains a constant game of cat and mouse.

“This is an arms race in maritime regulation and enforcement,” says Tholin. “The shadow fleet evolves faster than the rules. Every time we identify one tactic, they invent another.”

The stakes are high. Europe relies heavily on secure energy imports, and any disruption in maritime safety could have wide-ranging economic and environmental consequences. Governments are concerned that an accident involving these vessels could result in oil spills affecting sensitive ecosystems, disruption of international shipping lanes, and significant economic losses.

For Swedish coastguard officers like Tholin, the work is as much about vigilance as enforcement. They patrol the Baltic Sea in an environment where commercial shipping and sanctioned oil tankers operate in close proximity, constantly monitoring, verifying documentation, and communicating with vessels in real time.

“This is the front line,” Tholin says. “We see the ships, we track them, and we gather information. But our hands are tied in many ways. The challenge is to maintain control without overstepping legal boundaries.”

The European shadow fleet crisis reflects a broader trend in international trade, where sanctions and global economic pressures intersect with maritime law and technological loopholes. While sanctions aim to restrict Russian oil revenues, the shadow fleet demonstrates how complex global networks can undermine regulatory frameworks, leaving authorities scrambling to respond.

Looking ahead, analysts suggest that cooperation between European nations, increased satellite monitoring, and tighter scrutiny of insurers and port authorities will be critical. However, the fundamental challenge remains: as long as vessels can operate without a valid flag and obscure their movements, enforcement will remain limited.

Experts also warn that as these shadow fleets continue to operate, the risk of accidents – ranging from collisions to environmental disasters – will only grow. The combination of outdated vessels, unregulated crews, and complex shipping practices poses a persistent threat to both the environment and global maritime security.

“This is not just about sanctions,” Bockmann notes. “It’s about accountability, safety, and international order. If we cannot hold these ships to basic standards, the consequences could be catastrophic.”

The battle against Russia’s shadow fleet is ongoing, and European authorities acknowledge that it is a protracted struggle. The stakes – geopolitical, environmental, and financial – are significant, and the ability to enforce compliance will require constant innovation, vigilance, and international cooperation.

As the Baltic waters continue to host this unfolding maritime drama, Swedish coastguards and their European counterparts remain on watch, navigating a precarious balance between legal constraints and the urgent need to uphold sanctions, protect the environment, and ensure safe seas for commerce.