Despite hundreds of passages by sanctioned shadow fleet vessels through Danish waters in 2024, experts warn that current EU sanctions are not enough to cripple Russia’s oil revenue. The vessels pose an environmental and national security risk, yet the Kremlin continues to expand operations as enforcement struggles to keep pace.
Shadow Fleet Activity Surges in Danish Waters
Danish authorities have for the first time systematically tracked shadow fleet vessels passing through the country’s waters. The results paint a troubling picture of sanctions evasion on a massive scale.
292 Registered Passages in 2024
The Danish Maritime Authority registered 292 passages by EU-sanctioned vessels through Danish waters in 2024. This marks the first year authorities have systematically monitored and documented these shadowy operations. The ships typically sail under foreign flags of convenience and maintain questionable ownership structures that make enforcement difficult, raising concerns about both transparency and security risk.
When maritime authorities attempt to contact these vessels for certification checks, crews often simply refuse to respond. This pattern of non-cooperation has become a hallmark of shadow fleet operations. The vessels carry what is suspected to be sanctioned Russian oil, though cargo manifests frequently prove unreliable or falsified.
Dramatic Growth Since Invasion
Shadow fleet traffic has exploded since Russia’s full-scale invasion of Ukraine. Between January and August 2024, tankers carrying Russian oil through Danish straits increased by 277 percent compared to the same period in 2022. During that window alone, 46 million tons of Russian oil passed through the Baltic Sea.
The proportion of shadow fleet vessels has also grown dramatically. In 2023, these ships accounted for 46 percent of all tankers traveling from Russia through the Great Belt. By 2024, that figure had climbed to 61 percent. This escalation reflects Russia’s systematic effort to maintain oil revenues despite Western sanctions.
National Security Risk Increasing
Beyond economic sanctions evasion, shadow fleet operations increasingly represent a potential national security risk. Experts warn these vessels could serve multiple purposes in Russia’s hybrid warfare strategy.
Potential for Sabotage and Surveillance
Yevgeniy Golovchenko, an adjunct professor at the University of Copenhagen who researches the shadow fleet, describes these vessels as a potential threat to Danish national security. The ships are suspected of conducting surveillance operations and potentially participating in sabotage against critical infrastructure. This approach represents a core element of hybrid warfare, which seeks to damage adversaries while keeping conflicts below the threshold of formal war.
The connection between shadow fleet vessels and suspected sabotage operations has already emerged. Investigative journalism revealed that the Eagle S, later detained for allegedly damaging undersea cables between Finland and Estonia, had previously anchored at Skagen months before the incident. This discovery has amplified concerns that shadow fleet operations extend beyond simple sanctions evasion.
Environmental and Financial Risks
On top of the security risk, the vessels themselves pose catastrophic environmental risks. Many consist of aging tankers purchased over the past two years through opaque corporate structures. They frequently operate without adequate safety standards or proper documentation, with some disabling transponders to avoid tracking.
Less than half of shadow fleet vessels maintain valid insurance coverage. Many operate under policies from Russian insurer Ingosstrakh that automatically void coverage if sanctions violations are detected. This creates a liability vacuum where Denmark and other coastal states would bear all cleanup costs in case of disaster. A single major oil spill could cost up to 5.9 billion Danish kroner.
Sanctions Show Limited Effectiveness
While EU sanctions against individual vessels appear to reduce their activity, the overall impact on Russia’s economy remains insufficient according to multiple experts. The challenge lies in the scale and adaptability of shadow fleet operations.
Individual Vessels Affected but Fleet Expands
Research by Golovchenko indicates that sanctions do affect individual vessels. When a shadow fleet ship is placed on an EU sanctions list, its activity typically decreases by 80 to 90 percent. Sanctioned vessels also enter ports half as often as comparable unsanctioned ships.
However, this vessel-by-vessel approach has not significantly disrupted Russia’s overall oil export capacity. The country simply adds new vessels to replace sanctioned ones. During Denmark’s EU presidency alone, 250 new ships were added to the sanctions list, which now includes 599 vessels. Despite this growth in sanctioned vessels, Russian oil continues flowing through Danish waters at high volumes.
Economic Pressure Insufficient
Flemming Splidsboel, a senior researcher at the Danish Institute for International Studies, characterizes the Russian economy as pressured but far from collapse. Sanctions and the costs of the Ukraine war have created strain, yet Russia remains dependent on and sustained by oil revenues. Oil exports provide the largest injections into the Russian economy, making this sector both the most important and most vulnerable target.
Current sanctions have not been enough to bring Russia to its knees economically. Splidsboel expects shadow fleet operations may actually increase as Russia proves willing to invest more resources in circumventing restrictions. The vessels have demonstrated effectiveness despite operational difficulties, creating incentives for continued and expanded use.
Denmark Responds with New Measures
Danish authorities have begun implementing more active countermeasures, representing the first significant governmental response to shadow fleet operations in Danish waters. However, enforcement faces jurisdictional and coordination challenges.
Port State Control Inspections
The Danish Maritime Authority now conducts port state control inspections on older tankers anchoring at Skagen Red. Authorities can detain vessels that pose a security risk or environmental threats to Danish marine areas. Inspections focus on verifying valid insurance certificates, crew documentation, and vessel safety standards.
Skagen Red lies within Danish territorial waters, where Denmark maintains broad inspection authority. However, shadow fleet operators may simply relocate operations beyond the 12 nautical mile limit to avoid controls. This jurisdictional boundary creates enforcement complications, as vessels can still access services and conduct crew changes just outside Danish legal reach.
Defense Ministry Involvement
Danish Defense Minister Troels Lund Poulsen has stated the government views Russian attempts to circumvent maritime sanctions with great seriousness. The Danish Defense monitors particularly interesting vessels in Danish waters, elevating shadow fleet activity from a maritime issue to a national security risk. This policy shift acknowledges that shadow fleet operations may form part of broader Russian strategy to test Western resolve and create infrastructure vulnerabilities.
The Ministry of Foreign Affairs maintains that Denmark’s sanctions work is showing results. Officials point to falling Russian oil export revenues in recent months as evidence of effectiveness. Denmark has assembled a group of countries to coordinate on shadow fleet challenges and discuss additional international measures. However, critics argue current approaches remain insufficient given the scale of continued operations.
Enforcement Gaps and Future Outlook
Despite new measures, significant challenges remain in effectively countering shadow fleet operations. Coordination problems, resource limitations, and legal complexities hamper comprehensive enforcement.
Jurisdictional and Legal Limitations
Port state control inspections can identify documentation deficiencies and a security risk, but investigating sanctions violations requires separate legal pathways. This separation of competencies creates enforcement gaps. While missing insurance certificates provide clear grounds for detention, determining beneficial ownership and tracing sanctions violations demands coordination with financial and intelligence authorities operating on different timelines.
The shadow fleet problem extends across Northern European waters, affecting Sweden, Finland, and Germany as well. However, no centralized EU enforcement mechanism exists. Coordination depends on bilateral agreements and voluntary information sharing, which lacks the integrated oversight necessary for comprehensive sanctions enforcement. Implementation faces resource constraints across multiple jurisdictions.
Data and Verification Challenges
No publicly accessible comprehensive statistics exist on total shadow fleet passages through Danish straits. Many vessels disable transponders or operate under false flags, creating opacity that complicates evidence-based policymaking. The figures cited in reports derive from specialized analytical firms using tracking methods that combine automatic identification systems with satellite imagery, but significant gaps remain.
Experts recommend Denmark intensify maritime traffic surveillance through advanced radar and satellite technology. Establishing requirements for valid insurance documentation and strengthening international cooperation with the International Maritime Organization and EU bodies could improve enforcement. However, the adaptive nature of shadow fleet operations means Russia will likely continue finding ways to circumvent restrictions as long as oil revenues remain essential to funding military operations.
Sources and References
The Danish Dream: Denmark Invests in Defence in the Face of Rising Threats
DR: På trods af sanktionerne sejlede skyggeflåden sidste år igennem Danmark mindst 292 gange
Danwatch: Danmark vil kontrollere skyggeflåden
Information: Nu vil Danmark kontrollere den russiske skyggeflåde ved Skagen
Fiskerforum: Skyggeflåden udgør kæmpe risiko for havmiljøet og fiskeriet
