Russia has become the leading flag state for the so-called shadow fleet of sanctioned tankers, according to analysis by maritime intelligence firm Windward. The country has absorbed roughly 69 sanctioned vessels into its registry since November 2025, a shift Windward links to increased interdiction of stateless tankers by U.S. and European naval forces.
According to Windward, more than one in five of the over 1,000 tankers sanctioned by Western regulators now flies the Russian flag. Cameroon’s open registry ranks second, accounting for 16.5%, or 157 vessels, while Sierra Leone holds 98 ships. Windward reports that Cameroon’s government expelled around 55 Western-sanctioned tankers from its registry between February and May, stating the vessels had not been legitimately registered.
Flag-Hopping and Fraudulent Registries
Windward’s analysis found that at least 20 of the 157 ships still associated with Cameroon falsely broadcast that flag affiliation even after being de-registered. The report notes that Russian state-owned insurers have increasingly provided P&I and hull coverage to shadow fleet vessels over the past 18 months, while the Russian Maritime Register of Shipping has expanded its classification services to tankers beyond those flagged in Russia. Windward states that 98 tankers reflagged to Russia during 2025 and 2026, bringing the total Russia-flagged shadow fleet tally above 213 vessels.
According to Windward, the UK and EU have jointly sanctioned more than 650 aging tankers since late 2023, all used to transport sanctioned oil from Russia, Iran, or Venezuela. The firm reports that Western governments have pressured national maritime authorities to expel these vessels, though many smaller nations were unaware that contracted registry operators had added shadow fleet tonnage without proper oversight.
Windward identifies 23 countries — including Aruba, Angola, Guyana, Nicaragua, and Syria — whose registries the IMO has determined lack legitimate international ship registration frameworks, leaving associated vessels effectively stateless. The analysis adds that Syria, Eritrea, and Myanmar emerged as additional fraudulent registries identified in 2026.
Equatorial Guinea and Cameroon Case Studies
Windward’s report highlights Equatorial Guinea as an example of smaller nations being exploited for shadow fleet logistics. Of 38 sanctioned tankers flying its flag, 36 joined the registry in 2026, and Windward found no verifiable ship registry details listed with the IMO’s GISIS system as required. A Turkey-based company that previously claimed to manage the registry told Windward its contract had been suspended.
Separately, Windward’s review of 38 tankers expelled from Cameroon’s registry on May 26 found that 24 continued falsely broadcasting Cameroon flag status via AIS. The vessels collectively recorded 117 flag changes and 98 MMSI changes over three years, according to the analysis, with some tankers tracked taking uneconomical routes around Great Britain while sailing to and from Russian Baltic ports.
Does This Matter to You?
The expansion of Russia’s shadow fleet registry and the use of fraudulent or unverifiable ship registries carries implications for compliance and risk-screening processes across the maritime sector. According to Windward, vessels frequently change flags, names, and MMSI identifiers, complicating vessel screening and sanctions due diligence for parties involved in chartering, insurance, and bunkering.
The source material notes that AIS broadcasts from some vessels are unreliable, with ships falsely claiming flag affiliations after deregistration. This may be relevant for operators and compliance teams relying on flag state and AIS data when assessing counterparties or vessel history.
Gulf Bunkering does not provide operational or security guidance. This article is for informational purposes only. Operators should consult flag state authorities, P&I clubs, and relevant advisories for decisions relating to transit planning.
Sources: Windward (MIOC analysis by Michelle Wiese Bockmann, Senior Maritime Intelligence Analyst)
