Guest Post: Prof Pete Pedrozo on “Russia’s Shadow Fleet”

Heard about Russia’s “shadow fleet”?  A few weeks ago Germany seized an oil tanker alleged to be part of it, and more recently another tanker with a murky status was boarded and detained by the Estonian Navy as being a ‘stateless’ ship. 

These ships are just two of hundreds thought to be part of an illicit, global enterprise that is enabling Russia to evade sanctions on its oil industry that is so crucial to its ability to continue the war in Ukraine. 

But what is the legal status of this “shadow fleet”?  What can international law do about it?  Fortunately, we have one of the world’s top maritime law specialist to advise us:  Lawfire^® contributor Prof Pete Pedrozo.  He explains for us what it is, why it is such a serious concern, and – importantly – why it is so difficult to stop.

Russia’s Shadow Fleet 

Raul (Pete) Pedrozo

INTRODUCTION

In January 2025, German authorities seized a Panamanian-flagged oil tanker—the M/V Eventin—that was adrift in the Baltic Sea after it lost power and steering north of the German island of Rügen. The vessel was carrying 100,000 tons of crude oil from the Russian port of Ust-Luga to Port Said, Egypt. Without power and steering, the vessel was a hazard to navigation and, had it run aground, could have caused major environmental damage.

The Eventin was included in the February 2025 European Union’s (EU) sanctions package against Russia and is one of many aging oil tankers that make up Russia’s “shadow fleet.” The tanker and its cargo (worth $43 million) were subsequently confiscated by the German government in March.

Four months later, in April 2025, the Estonian navy detained and boarded a shadow fleet oil tanker—the Kiwala—that was on the EU sanctions list for allegedly sailing without a valid flag while the vessel was en route to Russia. Although the tanker was flying a Djibouti flag at the time of the seizure, Djibouti denied that the Kiwala was registered there. The vessel was therefore assumed to be stateless and legally boarded and detained by Estonian authorities.

So, what constitutes the so-called “shadow fleet?”

“SHADOW FLEET” DEFINED

The International Maritime Organization (IMO) defines the “shadow fleet” as ships engaged in illegal operations for the purposes of circumventing sanctions, evading compliance with safety or environmental regulations, avoiding insurance costs or engaging in other illegal activities.

These activities include:

(1) carrying out unsafe operations that do not adhere to international regulations and well-established and strict industry standards and best practices;

(2) intentionally avoiding flag and port State control inspections;

(3) not maintaining adequate liability insurance or other financial security;

(4) intentionally avoiding commercial screenings or inspections;

(5) not operating under a transparent corporate governance policy that assures the welfare and safety of those on board and the protection of the marine environment; or

(6) intentionally taking measures to avoid ship detection such as switching off their automatic identification systems (AIS) or long-range identification and tracking (LRIT) system transmissions or concealing the ship’s actual identity when there is no legitimate safety or security concern sufficient to justify such action.

Some experts argue that the IMO definition, which focuses on illegal practices, is too narrow and does not capture all of Russia’s efforts to circumvent the EU/G7 sanctions. The Kyiv School of Economics (KSE), for example, defines the term much broader to include all vessels that (1) lack Western insurance and use providers outside the International Group of Protection and Indemnity (P&I) Clubs and (2) are owned by non-EU/G7 countries.

Other organizations, like Windward, proposes a three-tiered system in lieu of “shadow fleet”—”cleared,” “gray,” and “dark” fleets. The “cleared fleet” includes tankers that do not exhibit any suspicious conduct. The “gray fleet” is a quasi-legal fleet comprised of about 1,000 vessels, managed by companies that obscure vessel origins and ownership. At first glance, gray fleet tankers appear to be law-abiding/non-sanctioned vessels.

However, because of their management structure, legality and sanctions compliance is difficult to determine. Gray fleet vessels also flag hop—frequently switch flags. The “dark fleet” is made up of about 1,300 vessels that employ deceptive shipping practices—e.g., disabling AIS, identification and location tampering—to transport oil.

THE OIL PRICE CAP

The Price Cap Coalition is comprised of the G7, the EU, and Australia. Following Russia’s unlawful invasion of Ukraine in 2022, the coalition agreed to prohibit the import of Russian-origin crude oil and petroleum products and established an oil price cap (OPC) mechanism on these commodities.

Western entities may only provide maritime transport and related services for Russian crude oil and petroleum products if these commodities are sold at or below the relevant price caps—$60 per barrel for seaborne Russian-origin crude oil, $100 per barrel for premium-to-crude petroleum products (e.g., diesel, kerosene, and gasoline), and $45 per barrel for discount-to-crude petroleum products (e.g., fuel oil).

Maritime transport and related services, which are normally dominated by Western companies, include trading and commodities brokering, financing, shipping, insurance (including reinsurance and protection and indemnity (P&I)), flagging, and customs brokering.

The intent of the OPC is to maintain a reliable supply of crude oil and petroleum products to the global market while reducing Russian revenues earned from oil. Decreasing Russia’s oil revenues affects Moscow’s ability to fund its illegal war effort since the oil and gas sector accounts for 60 percent of Russia’s export earnings and 40 percent of its budget revenues.

RUSSIA’S “SHADOW FLEET”

In response, Russia is circumventing the effects of the OPC by employing a fleet of aging tankers and soliciting new buyers that do not support the EU/G7 sanctions regimes. Shadow fleet vessels fly flags of convenience and are owned and managed by an intricate web of entities that obscure their linkage to Russia and allow them to operate without Western oversight. They also routinely employ tactics that conceal the origin of their cargo, to include illicit practices such as ship-to-ship (STS) transfers; AIS blackouts; broadcasting false positions; and transmitting false data.

By using non-Western insurance providers, the fleet can continue operations despite the sanctions. For example, a Norwegian company—Romarine AS—is being investigated by Norway’s Financial Supervisory Authority for providing fraudulent insurance certificates to shadow fleet tankers. The company is owned by a Russian citizen and its website is registered in St. Petersburg, Russia.

According to the KSE, Russia has spent $10 billion dollars to develop its shadow fleet. This has been accomplished by (1) shifting Russian-owned tankers to new management companies in other States; (2) buying vessels that are more than fifteen years old and therefore beyond the “insurance age” but were previously insured by the P&I Clubs; and (3) purchasing and repurposing vessels that are over twenty years old that would otherwise have been retired from service.

Older tankers are easier to scrap if subject to sanctions enforcement measures, thereby reducing financial risks and potential penalties for ship owners. Depending on the source, the size of the Russian shadow fleet ranges from 400 to 600 tankers. Of note, 40 percent of the shadow fleet is made up of former European and American tankers that were sold to companies in States like India, Vietnam, and the Seychelles that do not participate in the sanctions regime.

Shadow fleet tankers are known to fly flags of convenience, which complicates the ability of sanctioning authorities to trace oil cargoes back to Russian sources. These countries lack the ability or refuse to enforce the EU/G7 sanctions. Frequent reflagging of vessels among flags of convenience that do not enforce sanctions further complicates the ability to monitor and take enforcement action against Russia’s shadow fleet.

Flags of convenience used by the shadow fleet to transport Russian oil include Cook Islands, Eswatini, Gabon, Liberia, Malta, Marshall Islands, Palau, Cameroon, Saint Kitts and Nevis, Vietnam, and Panama.

In addition to flying flags of convenience, the shadow fleet operates under a complex structure that obscures ownership and management, including the use of shell companies, and allows Russia to conceal the real owners of cargoes or commodities. The primary countries providing management services to the shadow fleet include the United Arab Emirates, China, India, the Marshall Islands, and Turkey. India, China, and Turkey import 95 percent of Russian crude oil.

On average, three shadow fleet tankers loaded with Russian crude oil leave Russian ports daily, which represents around 800 voyages in 2024. Since sanctions were imposed, the amount of Russian oil being transported by the shadow fleet has steadily grown. By June 2024, Russia was shipping 4.1 million barrels of oil a day, constituting 89 percent and 38 percent of Russia’s seaborne exports of crude oil and oil products, respectively.

KSE estimates that during the first nine months of 2024, the shadow fleet allowed Russia to attain $10 per barrel more for its oil sales, which equates to over $8 billion in extra profits to sustain its war effort. Similarly, the monthly average of Russian crude oil transported by the gray fleet and dark fleet, using Windward’s categories, has risen 111 percent and 22 percent, respectively, since the beginning of the war. This accounts for over 142 million barrels of Russian crude oil per day worth over $6 billion.

DECEPTIVE SHIPPING PRACTICES

Russia’s shadow fleet employs a wide range of deceptive and illegal shipping practices to evade the /EU/G7 sanctions. The more prominent measures used by the shadow fleet include STS transfers; AIS blackouts; spoofing (falsifying their positions and transmitting false data); and changing the ship’s name or its IMO number.

While STS transfers at sea are common in the shipping industry, at-sea transfers of Russian-origin oil, sometimes on multiple occasions, make detection move difficult at its ultimate destination by obfuscating the oil’s origin. This can include blending Russian-origin oil with oil from other countries at sea. STS transfers are conducted in international waters (seaward of the territorial sea) near busy shipping lanes where coastal States lack oversight and enforcement authority.

In March 2025, a twenty-year old shadow fleet tanker—Andaman Skies—loaded with over 767,000 barrels of Russian crude oil was denied entry into an Indian port because it did not have the requisite seaworthiness certificates from a recognized classification society. The tanker has switched flags three times in the last two years—from Cook Islands, to Honduras, to Tanzania—and is purportedly insured by a Russian P&I company.

An apparent win for EU/G7 sanctions was soon dashed, however, when the Andaman Skies conducted a STS transfer to the Ozanno, a Sao Tome and Principe-flagged tanker that had delivered 730,000 barrels of Russia crude oil to Jamnagar, India in late March. The Ozanno is expected to deliver the oil to a port in western India in April 2025.

All vessels over 300 gross tons engaged in international voyages are required to use AIS. This mandatory carriage requirement enhances safety of navigation by providing a ship’s identity, location, speed, and destination to other nearby vessels and to shore-based monitoring systems.  With limited exceptions (e.g., when the crew’s safety is directly threatened), AIS operation should be continuous.

Frequent and prolonged blackouts used by shadow fleet tankers to hide their position or illicit activities (e.g., STS transfers) are prohibited. Similarly, broadcasting a false AIS signal to conceal a vessel’s true location, identity, or journey poses a safety risk to other nearby vessels and is therefore prohibited.

SHADOW FLEET CONCERNS

The IMO recognizes that shadow fleet tankers are improperly maintained, lack adequate insurance coverage, and avoid oversight or regulation by flag and coastal States. The IMO considers that these ships pose a “real and high risk of incidents,” particularly when they engage in STS transfers, and are a serious threat to the safety and security of international shipping, as well as to the protection of the marine environment.

Nearly 75 percent of the shadow fleet is comprised of tankers that are more than fifteen years old. Coupled with substandard maintenance and the use of deceptive shipping practices (e.g., going dark), the risk of malfunction or collision increases significantly, which could result in an oil spill with serious environmental consequences.

Given that the ships lack adequate insurance from reputable providers, the financial burden of responding to an incident (e.g., performing environmental mitigation, repairing infrastructure, conducting search and rescue or salvage) will be the responsibility of the aggrieved coastal States.

Since 2022, there have been over 50 incidents involving Russian shadow fleet tankers that could have resulted in environmental damage.

For example, two flag-hopping shadow fleet tankers required the assistance of tugs and a salvage ship after they experienced mechanical malfunctions in the Bay of Gibraltar. Similarly, an 18-year-old shadow fleet tanker transporting 340,000 barrels of Russian oil products from the Russian port of Vysotsk lost engine power and nearly ran aground in the Danish Straits.

Use of deceptive shipping practices, such as illicit STS transfers or disabling or spoofing AIS transmissions, create navigational hazards for other vessels operating nearby and raise the risk of collision, particularly in crowded shipping lanes and the approaches to international straits.

Similarly, shadow fleet vessels routinely disregard international regulations, ignore established industry standards and best practices, and intentionally avoid flag and port State control inspections. This adds to the risk of malfunctions and maritime accidents.

Numerous incidents involving Russian shadow fleet tankers—e.g., fires, engine malfunctions, collisions, loss of steerage, and oil spills—confirm these maritime safety concerns. In May 2023, for example, the Gabon-flagged shadow tanker Pablo caught fire off the coast of Malaysia.

Malaysian authorities responded, rescuing the crew, extinguishing the fire, and cleaning up the resulting oil spill, all at the expense of the Malaysian taxpayers. Only a few months later, in October, the twenty-six-year-old shadow tanker Turba, flagged in Cameroon, lost engine power 300 kilometers off the coast of Indonesia and had to be rescued by an Indonesian salvage team.

There is also growing evidence that Russia (and China) are both using shadow fleet vessels to engage in gray-zone operations, such as intelligence collection and intentional damage to critical underwater infrastructure.

In December 2024, for example, Finnish authorities seized the shadow fleet tanker Eagle S, registered in the Cook Islands, for intentionally damaging the Eastlink 2 submarine cable that connects Finland and Estonia by deliberately dragging its anchor over it. Repairs will take several months, which will be borne by the coastal States. The Eagle S was also equipped with hi-tech transmitting and receiving equipment typically used for intelligence collection. Swedish naval officials have likewise confirmed that shadow fleet tankers are actively monitoring the Swedish military base on Gotland Island in the Baltic Sea.  

ENFORCEMENT AUTHORITY LOOPHOLES

Although coastal States exercise complete control over their territorial sea, that sovereignty is subject to the right of innocent passage (UNCLOS, arts. 2(1), 17-19). Coastal States can clearly prevent a foreign-flagged vessel from conducting intelligence or intentionally cutting submarine cables in their territorial sea (UNCLOS, arts. 19(2)(c), 21(1)(c)), but if the activity occurs beyond the twelve-mile territorial sea limit, the coastal States’ response options are limited (UNCLOS, arts. 56, 58, 86-87, 92).

Coastal States could channelize oil and gas tanker traffic through their territorial sea to ensure safety of navigation by designating mandatory sea lanes and/or traffic separation schemes in their territorial sea (UNCLOS, art. 22(1)). Tankers would be required to use the sea lanes and traffic separation schemes, which would facilitate monitoring their location, but the coastal State could not outright prevent their innocent passage through the territorial sea (UNCLOS, art. 22(2)).

Arguably, to ensure safety of navigation and preservation of the marine environment, coastal States could adopt laws and regulations requiring all oil and gas tankers engaged in innocent passage to carry and produce evidence of reputable P&I insurance and seaworthy certificates (UNCLOS, art. 21(1)(a), (1)(c), (1)(f)). However, such laws would be difficult to enforce, unless the vessel enters port, and could be perceived by some flag States as an illegal impediment to the right of innocent passage.

Note that Denmark, Estonia, Finland, Poland, Sweden, and the United Kingdom announced that they were going to check insurance documents of suspect shadow fleet vessels in the English Channel, the Danish Straits, and the Gulf of Finland. Vessels that fail to voluntarily comply with the request for information will not be stopped and boarded but will be placed on a sanctions list.

Coastal States additionally have jurisdiction (though not sovereignty) in their exclusive economic zone (EEZ) to protect and preserve the marine environment (UNCLOS, art. 56(1)(b)(iii)), but enforcement jurisdiction over foreign-flagged vessels is limited.

Proceedings may only be instituted against a foreign-flagged vessel in cases where there is clear objective evidence that the vessel’s violation of applicable pollution prevention rules and regulations in the EEZ resulted in a discharge causing major damage or threat of major damage to the coastline or related interests of the coastal State, or to any coastal State resources in the territorial sea or EEZ (UNCLOS, art. 220(6)).

Port States have complete sovereignty over internal waters and are therefore in the best position to enforce sanctions and demand valid certificates of insurance required by IMO liability and compensation conventions (UNCLOS, art. 2). Port States may also impose conditions on port entry (e.g. provide proof of adequate P&I insurance, classification society inspection certifications, cargo manifests) on foreign-flagged vessels and take the necessary measures to prevent any breach of those conditions (UNCLOS, art. 25(2)).

Moreover, port States have jurisdiction to enforce violations regarding the use of AIS. So, if a shadow fleet tanker has engaged in AIS blackouts or spoofing, port State authorities could detain, investigate, and fine the vessel, as well as prevent it from unloading its cargo.

Unfortunately, port State enforcement measures are not universally applied for various reasons ranging from lack of capacity to apathy. Thus, shadow fleet vessels routinely avoid ports where sanctions and other enforcement measures are strictly enforced in favor of calling on ports where enforcement is lax.

The IMO has called on port States to better enforce safety and liability conventions on shadow fleet vessels, to include safety requirements relating to STS transfers. Coastal States are also encouraged to enhance their monitoring of STS transfers in their territorial seas and EEZs, and to take appropriate action in cases that do not comply with applicable maritime safety and prevention of maritime pollution regulations.

Monitoring is facilitated by Annex I of the International Convention for the Prevention of Pollution from Ships (MARPOL), which requires oil tankers that plan to conduct STS operations within the territorial sea or EEZ of another State to notify that coastal State at least 48 hours in advance of the scheduled STS operation (Annex I, reg. 42).

Records of STS operations must be retained on board for three years and must be made available for inspection upon request by port or coastal State authorities (Annex I, reg. 41). Shadow fleet tankers can avoid these requirements by conducting their STS transfers beyond the EEZ, or in EEZs of coastal States that do not strictly enforce these measures.

CONCLUSION

The G7 recently announced that it was creating a Shadow Fleet Task Force to better monitor, detect, and constrain the use of the shadow fleet tankers engaged in illicit, unsafe, and environmentally unsound practices.

Nevertheless, sanctions will only work if the international community, writ large, is invested in enforcing them. Russia is selling a commodity that is essential for the economic growth and well-being of all nations. Even the EU cannot wean itself off Russia petroleum products.

In year-three of the war, the EU imported €21.9 billion of Russian oil, exceeding the €18.7 billion of military and humanitarian aid they provide Ukraine in 2024. Additionally, with the return of great power competition between the United States, China, and Russia, the political landscape is not conducive to international consensus. Absent a change in these conditions, use of the shadow fleet to facilitate Russian oil sales can therefore be expected to continue unabated for the foreseeable future. 

About the author:

Captain Raul (Pete) Pedrozo, U.S. Navy (Retired), is the Howard S. Levie Chair on the Law of Armed Conflict and professor of international law at the Stockton Center for International Law, U.S. Naval War College. Prof. Pedrozo was the former senior legal adviser at U.S. Pacific Command and served as special assistant to the Under Secretary of Defense for Policy.

Disclaimers:

The views and opinions expressed in this article are those of the author and do not necessarily reflect those of the U.S. Naval War College, the U.S. Department of Defense, or the U.S. Government.

The views expressed by guest authors do not necessarily reflect my views or those of the Center on Law, Ethics and National Security, or Duke University. (See also here).

Remember what we like to say on Lawfire^®: gather the facts, examine the law, evaluate the arguments – and then decide for yourself!