Knowing who you are dealing with is getting harder. File Image / AI Generated

• 275 tankers broadcast fraudulent registry flags in Q2, according to Windward
• 1.24 million false ship-to-ship AIS meetings recorded in the same quarter, its data shows
• EU's 21st sanctions package lets vessels be designated for bunkering listed ships
• IMO says no single treaty defines fraudulent ship registration

A bunker supplier weighing up an enquiry has two important ways of establishing who it is dealing with.

The first is the vessel's certificate of registry, which confirms its identity and says whose flag it sails under, and the second is its AIS history, which says where it has been.

Not only are both now routinely faked, the cost of getting it wrong has just shifted from the shipowner onto the supplier.

In the second quarter of 2026, 275 internationally trading tankers were broadcasting the flag of a fraudulent registry, down from 290 in the first quarter, according to maritime intelligence firm Windward, which says it has now identified 22 such registries.

Around 90% of the tankers using them are under Western sanctions.

The First Check: A Flag That May Not Exist

The fraud is hard to spot because the legitimate model looks much the same.

Several of the world's largest open registries are run by private companies under contract to a government, an arrangement used by Liberia and the Marshall Islands and entirely proper.

A private firm announcing that it operates a smaller state's international registry is therefore unremarkable on the face of it.

The IMO's Legal Committee has settled on a definition of a fraudulent registry, describing it as an unauthorised body that intentionally misrepresents that it is authorised to register ships on behalf of a flag state.

The simplest version is a registry that does not exist at all, where ships broadcast the flag of a country that operates no international registry whatsoever.

A second version is a private company issuing a real state's flag without that state's authority, and a third is what the IMO calls the terminated registry, where a ship keeps flying a flag after its registration has expired or otherwise ended.

A fourth exploits provisional registration, which open registries typically grant for three to six months with minimal due diligence while full documentation is awaited, with the vessel hopping to another flag before the provisional period expires.

When Windward first mapped the problem in August 2025 it counted at least 12 fraudulent registries, using the names of Angola, Aruba, Benin, Curacao, Eswatini, Guinea, Guyana, Mali, Malawi, Mozambique, Sint Maarten, and Timor-Leste, with Guyana alone accounting for 36% of falsely flagged sanctioned ships.

None of those 12 states operates an international registry, Windward notes, which under the IMO's definition makes any vessel broadcasting their flag false.

Its quarterly tracking shows the count has climbed steadily since, reaching 18 by the end of 2025, 20 at the close of the first quarter, and 22 in the second, even as the number of tankers flying those flags has stayed flat to falling, at 285, 290, and 275 over the past three quarters.

Windward reads that divergence as seizure pressure pushing operators toward legitimate but permissive registries that are prepared to take on sanctioned ships, with flag hopping down 26% in the first quarter.

What That Looks Like

Cameroon shows what it looks like when a real state is used as cover.

In February its transport ministry suspended new registrations to the country's international registry, citing several cases of fraudulent registration carried out through unauthorised applications, which the government has attributed to cyber fraud.

By then around 180 tankers were using the registry, more than 120 of them sanctioned, which at the time made Cameroon the second-largest registry for sanctioned shadow fleet tankers after Russia.

In June the EU's Operation IRINI boarded three tankers, the Nelsa, Oneiroi, and Sandhya, and found all three carrying fraudulent Cameroonian papers, and by early July 39 vessels already on the books had been struck off.

Windward notes a number of suspicious registries have shown an unusual growth curve.

Barbados, the Cook Islands, and Gabon all grew at record pace over 2023 and 2024, in some cases tripling in size within 12 months by taking on 100-plus tankers, then shrank just as fast once those ships were sanctioned and moved on.

Gambia's maritime authority informed the IMO in October 2024 that a Cyprus-incorporated company was now operating its international registry, after which the fleet grew by 626% in a single quarter and gross tonnage by 1,038% over the 12 months to mid-2025.

The Second Check: An AIS History That May Be Invented

Checking a vessel's AIS history is another key step for suppliers, especially if the vessel's identity may be in question.

However, that check may be weakest when it is needed most.

Windward has recorded 3.35 million false ship-to-ship meetings since February 28 this year, AIS encounters that never physically took place, with 1.24 million of them falling in the second quarter alone.

Spoofing of that kind does not hide a vessel's position but invents one, planting meetings and movements in the very record a supplier later checks.

GPS jamming, which denies a position rather than fabricating it, affected 171,286 distinct vessels in the second quarter, Windward says, down 8% on the quarter and 35% below its late-2025 peak of 262,117, with jamming heaviest where and when US forces have been operating, in the Gulf, the Baltic, and the Black Sea.

A vessel's broadcast track may reflect injected coordinates rather than actual movements, which makes it difficult to establish whether a ship has called at ports within sanctioned jurisdictions or conducted a ship-to-ship transfer with a designated vessel.

Where the Liability Sits Now

Until recently liability was primarily an owner's and an insurer's problem.

The EU's 21st sanctions package, adopted on July 23, changed that by extending the designation criteria to cover vessels that support the shadow fleet by providing services, with bunkering named explicitly.

The new ground reaches vessels rather than companies.

A trader or physical supplier without tonnage of its own sits instead under the asset freeze regime, which has already caught a bunkering operator.

The Council applied the new ground at once, designating five bunkering vessels on the basis that they had regularly refuelled tankers already on the list, as Paul Henty, a partner at Beale & Company, set out in an analysis for Ship & Bunker last month.

"Supply a designated vessel and you were in breach. Supply designated vessels often enough and you can end up on the list yourself," wrote Henty.

There is no numerical threshold, no measurement period, and no safe harbour, he noted, and the listing criterion does not ask what the supplier knew.

That matters because, in Henty's words, the shadow fleet is built to defeat screening.

"Names change, flags change, AIS positions are manipulated, and a stem that came back clean on every check available at the time can turn out to have been supply to a vessel already on the list," he wrote.

"The list tells you who is caught. It no longer tells you whether you are about to join them."

What the Authorities Are Doing

What makes this difficult to police is that the framework is thin.

The IMO states that there is currently no single specific international instrument or treaty containing a standardised or universally accepted definition of fraudulent ship registration, and that its Legal Committee agreed working definitions only at its 108th and 109th sessions in 2021 and 2022.

Combating fake registries appears to rest largely on flag states discovering and disowning impersonations of themselves, which is how Cameroon's registry came to be suspended.

The IMO has published around 30 such communications from states and territories since 2015, and says nearly 40 member states have experienced fraudulent use of their flags by criminal groups.

Its main response came in April, when the Legal Committee approved its first guidelines on ship registration, covering due diligence on ownership and ship identity, eligibility checks, quality assurance, information sharing, and control over the ship registration authority.

The guidelines are non-binding, and the IMO notes there is still no binding international framework regulating the registration of ships.

A Secretariat note circulated ahead of the session (LEG 113) put the count at 529 falsely flagged vessels, 356 of them not classed by any society.

Brussels and London have already shown they will reach past the ships to the people running the flags.

In July 2025 the EU and UK both sanctioned Intershipping Services LLC, a UAE company contracted by Gabon since 2019 to operate its international registry.

At sea, 14 EU and UK coastal governments declared in January that they would act against unsafe Russia-trading tankers sailing without a flag or using deceptive practices, and European navies have since boarded and detained stateless and falsely flagged tankers, with nine ships seized by French, Belgian, British, and Swedish navies since the start of 2026.

The most recent move came on August 24, when the US Treasury named shipping a sector of the Iranian economy, allowing OFAC to designate any person operating in the sector regardless of where they are located.

In the same action, OFAC designated five bunker companies, accusing them of fuelling tankers carrying Iranian crude and vessels linked to Iran's national shipping line.

None of those designations rested on the new shipping determination, with all made under existing petroleum and proliferation authorities, but Henty told Ship & Bunker the action is the clearest example there has been of liability moving onto the supplier.

On AIS, the long-term fix on offer is a new system rather than a patch.

In May the IMO's Maritime Safety Committee adopted regulations introducing the VHF Data Exchange System, or VDES, a voluntary alternative to AIS that adds authentication to reduce the risk of spoofing, with the rules expected to enter into force on January 1, 2028.

Carriage will not be mandatory, and AIS is not being replaced.

In the meantime the response is detection and seamanship, with EMSA running a working group with member states on detecting AIS spoofing and GPS jamming, and P&I clubs such as Skuld advising members to verify position by all available means and report interference to UKMTO and their flag state.

But little of that helps a supplier reading a vessel's track today.

What It Means for Suppliers Now

For the supplier, knowing who you are dealing with is getting harder, and the cost of getting it wrong is getting higher.

Windward's advice to suppliers is that list-based screening alone is no longer a defence, and that flag history, ownership structure, and behaviour need checking together, with movements verified against satellite imagery and radio-frequency detection rather than AIS alone.

Henty's advice is about records as much as screening, and comes in three parts.

Hold bunkering history in a form that can be interrogated by counterparty and by vessel over time, set internal triggers on repeat dealings rather than single deliveries, and write down the reasoning whenever a relationship is paused or ended.

Henty also cautions against mistaking what each check is for.

"A certificate of registry is an identity and flag status check, not a substitute for designation screening against the vessel's IMO identity, which does not change when the flag is faked," he told Ship & Bunker.

"Read your sanctions clause and ask what has to have happened before you are entitled to stop," wrote Henty, because if the answer is a breach, a designation, or a listing, all three arrive too late.

It is advice worth following.

If the flag turns out not to exist, there is nothing standing behind the vessel a supplier has just fuelled, and they may be the ones left holding the exposure.