As 2025 drew to a close, approximately 285 internationally trading tankers were broadcasting via AIS under the flag of a fraudulent or unknown registry, according to Windward.
False flagging has evolved from a niche compliance concern into a widespread risk in global shipping. With stricter sanctions enforcement, more vessels are now operating without a valid nationality while still engaging in international trade. Analysis conducted by Windward has identified 18 fraudulent registries, as defined by the International Maritime Organization (IMO).
A striking 91% of vessels using these fraudulent registries were already sanctioned by Western authorities, underscoring the increased pressure dark fleet tankers face in finding a legitimate regulatory home to continue trading.
Moreover, the most frequently used fraudulent registries were Guinea (51 ships), Netherlands Antilles (45), Guyana (44), and Aruba (24).
False flags at scale in Iran-linked shipping
Windward examined more than 540 tankers and gas carriers linked to Iran-related trade. Nearly 40% were found to be falsely flagged, either by using fraudulent registries or by falsely claiming registration with legitimate flag states, based on International Maritime Organization records.
Furthermore, more than 300 of these vessels were already sanctioned by the United States, the United Kingdom, or the European Union.
Many were older tankers, averaging 22 years of age, operating without valid insurance or recognized certification once their false flag status was established.
