This investigation delves deep into the covert operations of Russia’s so-called “shadow fleet” , a clandestine maritime network designed to circumvent international sanctions, particularly those targeting Russian oil exports in the wake of its invasion of Ukraine. By examining the evolving mechanisms behind sanctions evasion, the report highlights the legal grey zones exploited by these vessels, including frequent flag-hopping, rebranding, and deceptive shipping practices such as AIS manipulation and illicit ship-to-ship transfers. Drawing on recent policy workshops, expert interviews, and maritime intelligence, the report argues that traditional enforcement measures are no longer sufficient. Instead, a new comprehensive, multi-faceted strategy is needed, one that leverages international legal instruments, strengthens insurance enforcement, and targets all elements of the logistics chain. Through real-world case studies and legal analysis, this report provides a critical lens on how Russia continues to undermine global sanctions regimes and what the international community can do to respond.
Investigation Team
In the wake of Russia’s full-scale invasion of Ukraine in 2022, a series of comprehensive sanctions were imposed by Western countries targeting key sectors of the Russian economy. Chief among these measures were restrictions on the export of Russian oil, a major source of revenue for the Kremlin. Yet, despite these sweeping sanctions, Russia has continued to export oil, often at scale. How is this possible? One significant answer lies in what has come to be known as Russia’s “shadow fleet.”
This fleet, composed of aging tankers operating under opaque ownership structures and often registered under flags of convenience, has allowed Moscow to maintain a lifeline to global markets, particularly in Asia. This investigative report dives deep into the mechanics of this clandestine operation, the international legal gaps it exploits, the responses from global governments, and the path forward.
The Anatomy of the Shadow Fleet
The term “shadow fleet” refers to a network of vessels used to transport Russian oil in ways that circumvent sanctions and regulatory oversight. These ships are typically older, less insured, and lack proper classification. Many operate under obscure ownership via shell companies registered in countries with lax maritime enforcement. They often disable AIS (Automatic Identification System) tracking, conduct ship-to-ship transfers in international waters, and operate under jurisdictions that shield them from scrutiny.
The emergence of this fleet isn’t a new phenomenon. It borrows heavily from strategies long employed by sanctioned states like Iran and Venezuela. However, what sets Russia’s shadow fleet apart is its scale. Analysts estimate it to number in the hundreds, with a capacity large enough to sustain significant volumes of crude oil exports.
Legal and Regulatory Loopholes
A key enabler of the shadow fleet’s operations is the fragmented and often contradictory nature of international maritime law. The United Nations Convention on the Law of the Sea (UNCLOS) provides a broad framework for maritime operations but leaves significant discretion to flag states. As a result, vessels operating under flags of convenience – like Panama, Liberia, and the Marshall Islands – enjoy relative impunity when they violate norms.
Another critical loophole lies in insurance and classification. Many Western insurers, such as those under the International Group of P&I Clubs, have ceased covering Russian cargoes. In response, many shadow fleet vessels have turned to lesser-known, non-Western insurers or operate without adequate insurance at all. This creates substantial risks not just for enforcement but also for environmental safety.
A Changing Risk Landscape
There is growing concern that the shadow fleet is not just a mechanism for economic evasion but may also be contributing to broader hybrid threats. Shadow fleet vessels have been implicated in environmental accidents, maritime obfuscation, and in some cases, suspected intelligence operations. This has led some Western security analysts to view them as more than just a financial loophole — but as potential threats to maritime stability and security.
In November 2024, the International Institute for Strategic Studies (IISS), in collaboration with the Royal Navy Strategic Studies Centre, held a workshop bringing together key stakeholders from government, academia, and the maritime industry. The consensus: a new strategy is needed — one that addresses not just individual vessels, but the entire ecosystem enabling their operations.
Legal Dilemmas and Strategic Risks in Enforcing Action Against the Shadow Fleet
Within the framework of the United Nations Convention on the Law of the Sea (UNCLOS), coastal states are granted specific rights to safeguard their territorial waters and Exclusive Economic Zones (EEZs) against threats, including violations of international law, maritime security risks, and environmental hazards. However, these rights must be carefully balanced against UNCLOS provisions that guarantee the right of innocent passage through territorial seas and unimpeded transit through international straits such as the English Channel. Crucially, UNCLOS emphasizes that such provisions must not be enforced in a manner that discriminates against any particular state.
The threshold for intercepting, boarding, or seizing vessels is deliberately set high under international law. Any preemptive or coercive action requires “clear grounds” to suspect a threat to security or international legal norms, or demonstrable evidence of environmental risk such as a “significant discharge.” This legal burden of proof limits the scope for unilateral enforcement and underscores the importance of preserving freedom of navigation—a core principle of the rules-based international maritime order that Western states consistently uphold.
Nonetheless, advocates for a more assertive stance argue that there is legal flexibility in interpreting these thresholds, especially when dealing with sanctioned or deceptive maritime activities. They propose that shadow fleet operations—given their systemic role in undermining international sanctions—could be construed as security threats to coastal states, thus justifying interdictions under existing UNCLOS exemptions. However, such reinterpretation carries considerable geopolitical and normative risks.
There is a serious concern that if Western states pursue a more permissive approach under UNCLOS, it could set a precedent for other actors—such as China in the South China Sea, Iran in the Strait of Hormuz, or even Russia in Arctic waters—to justify their own controversial maritime behaviors. These states already face accusations of bending UNCLOS interpretations to serve national interests. Hence, any Western-led shift could further weaken the coherence of international maritime norms and reduce the West’s moral authority to contest such practices.
This raises two interconnected challenges. First, whether assertive maritime actions—like seizing or boarding vessels suspected of sanctions violations—could gain broad international legitimacy in the absence of multilateral frameworks, such as a UN Security Council resolution. Second, whether such a strategy would alienate neutral or “hedging” states whose cooperation is crucial to effectively isolating shadow fleet networks.
A historical precedent underscores these risks. In 2019, the British seizure of the Iranian tanker Grace 1 in Gibraltar led directly to Iran’s retaliatory seizure of the UK-flagged Stena Impero. The diplomatic fallout highlighted the tit-for-tat potential of maritime enforcement actions and the broader geopolitical ripple effects they can provoke.
Therefore, any attempt to reinterpret the right of innocent passage or expand the legal basis for interdictions must be underpinned by a transparent, evidence-based framework—ideally supported by a critical mass of international actors. Establishing an internationally recognized ‘due process’ mechanism for designating and sanctioning shadow fleet vessels would be pivotal. This would not only enhance legitimacy and compliance but also help prevent arbitrary or politically motivated enforcement.
The fundamental questions that remain are whether there is sufficient political will among key maritime states to pursue such a path—and, if so, whether they have the institutional capacity, naval assets, and diplomatic bandwidth to implement and sustain it effectively.
Case Study 1: Ship-to-Ship Transfers in the Mediterranean
One illustrative case involved a Greek-owned tanker, the Sea Pegasus, which conducted a series of ship-to-ship (STS) transfers with a sanctioned Russian vessel off the coast of Malta. Despite the maneuver occurring in international waters, the cargo’s destination – a refinery in India – meant that it had effectively bypassed EU sanctions.
The case gained attention after satellite imagery and AIS data compiled by investigative journalists showed the STS transfer occurring under cover of darkness, with the vessels’ tracking systems disabled. While Greek authorities launched an investigation, no legal consequences were imposed due to jurisdictional limitations.
Case Study 2: The Indian Refinery Connection
India has emerged as a significant buyer of Russian oil post-sanctions. In one notable case, a shadow fleet vessel carrying crude oil loaded in Russia was reflagged mid-journey and delivered to a private Indian refinery. When confronted, refinery officials claimed they were unaware of the oil’s origin due to the change in paperwork and vessel identity.
This episode underscores how paperwork manipulation, coupled with regulatory opacity in receiving countries, enables shadow fleet operations. While India has not formally joined Western sanctions, the case raises questions about the extent of complicity or negligence among importers.
Case Study 3: Environmental Risk in the Baltic Sea
In December 2024, a shadow fleet tanker, the Volga Star, suffered a minor spill in the Baltic Sea near Swedish waters. The ship, which was over 25 years old and insured through an obscure Russian firm, had been carrying crude oil from the port of Primorsk. Due to inadequate safety standards and a poorly maintained hull, the vessel experienced a leak during a routine maneuver.
Swedish authorities criticized the lack of international oversight and raised the alarm about the environmental hazards posed by aging, unregulated vessels operating in critical marine environments. The Volga Star incident triggered renewed calls within the EU for stricter port-entry requirements based on vessel age, classification, and insurance coverage.
Case Study 4: The Ghost Tanker in the Suez
In early 2025, a so-called “ghost tanker” – a vessel sailing without AIS and using forged documentation – was detained by Egyptian authorities while transiting the Suez Canal. The ship, ostensibly empty, was found to have significant traces of Russian crude oil.
The investigation revealed a network of fake shipping documents, forged bills of lading, and a circuitous route that involved port calls in North Africa. Egypt, eager to maintain its role as a neutral trading hub, quietly released the vessel after minor fines. However, the case highlighted the challenges facing transit states in enforcing sanctions without jeopardizing trade revenues.
Options for Enforcement and Policy Responses
- Reinterpreting ‘Innocent Passage’: Some maritime legal scholars argue that the right of innocent passage, as enshrined in UNCLOS, could be challenged if the vessel is facilitating sanction violations or posing environmental risks.
- Blacklist-Based Port Denial: Ports could adopt a shared blacklist of vessels suspected of being part of the shadow fleet. Denying port access would raise operational costs for shadow operators.
- Environmental and Safety Restrictions: Governments can introduce stricter environmental and safety regulations, particularly targeting older vessels and those without sufficient insurance.
- Transparency in Cargo Ownership: Greater focus on cargo origin and end-users, rather than just vessels, could improve enforcement. This may involve enhanced due diligence requirements for importers and refiners.
- International Coalition Enforcement: A coordinated effort involving NATO navies or a coalition of willing states could help enforce sanctions in international waters, though this raises concerns about escalation and legal overreach.
Russia’s shadow fleet represents a complex challenge at the intersection of maritime law, geopolitics, and economic enforcement. While piecemeal responses may offer temporary relief, a truly effective solution will require an integrated strategy that brings together legal reform, international cooperation, and private sector accountability. Until then, the shadow fleet will continue to sail — not just through international waters, but through the cracks in the global legal and regulatory order.