The Dark Fleet, Lifeline of Sanctioned Oil Revenues, Is Under Attack

The U.S. government’s seizure of Skipper, alongside Ukraine’s drone attacks in the Black Sea, shows that the dark fleet of hundreds of flagless, stateless tankers can no longer operate unchallenged as they transport sanctioned oil and gas.

KNOCKOUT.

If you threaten our nation, or break the law, there is no place on land or sea where we won’t find you.

Thank you to the brave service members from @USCG, @ICEGOV, @FBI, @DeptofWar, and @TheJusticeDept. pic.twitter.com/KUCRjES267

— Homeland Security (@DHSgov) December 11, 2025

Very large crude carrier Skipper (IMO 9304667) left Venezuelan waters this morning after U.S. forces boarded the ship on Wednesday by helicopter off the country’s coast.

Like the other three tankers hit by Ukrainian drones in the Black Sea over the past two weeks, the 20-year-old Skipper was flying the flag of a fraudulent registry and was effectively flagless and stateless.

Ukraine's SBU security service says its Sea Baby naval drones today struck another Russian “shadow fleet” tanker in the Black Sea.

Video from an SBU source purports to show the oil tanker "Dashan" being hit by the attack drone and explosions in the stern area. "The vessel,… pic.twitter.com/mtfBqYe1gQ

— Christopher Miller (@ChristopherJM) December 10, 2025

The seizure warrant for Skipper and its cargo of Venezuelan oil was issued by a federal judge who cited violations of U.S. sanctions laws. Skipper, then known as Adisa, was sanctioned back in November 2022 for its role in an oil-smuggling network funding Iran and Hezbollah.

A Growing Pool of Vulnerable False-Flag Ships 

Without the protection of a flag state, these four tankers were vulnerable to military intervention. They are among nearly 400 other false-flag tankers now viewed as legitimate targets, with nearly 20 currently at very high risk of imminent attack or seizure due to their location.

That includes 12 falsely flagged tankers identified in the Black Sea and seven ships in waters off Venezuela. Ukraine’s strategy to attack commercial ships has been highly targeted, focusing only on tankers in ballast and without flags.

There are roughly 400 tankers broadcasting via AIS that they are flagged with one of 19 fraudulent registries listed by the International Maritime Organization. Nearly 300 of these ships are already sanctioned.

Despite their flagless status, which invalidates insurance and class, these tankers continue trading and remain a vital lifeline to Iran, Venezuela, and Russia. They form part of a dark fleet of some 1,000 internationally trading crude tankers operating outside Western jurisdiction and delivering energy commodities that generate billions of dollars in revenue.

Most are elderly, poorly maintained, used solely for sanctioned oil or gas trades, and structured to obscure beneficial ownership behind labyrinthine shelf companies and brass-plate addresses around the world.

Numbers of falsely flagged ships have more than doubled in 2025, mirroring the increase in sanctions imposed by the U.S., EU, and UK.

Events over the past two weeks show that falsely flagged ships can no longer expect to operate outside the international rules-based order that underpins the regulatory integrity of 11 billion tons of global seaborne trade each year.

Flag Fraud, Legal Grounds, and Expanding Enforcement

Skipper was flagged with Guyana, which hasn’t had an international ship registry since 2021. All three Russia-trading tankers disabled by Ukraine’s Sea Baby drones were falsely flagged with Gambia, including Dashan (IMO 9299666), the latest ship attacked on Wednesday. Dashan, along with Kairos and Virat, were among 72 vessels listed last month by Gambia’s maritime authority as having fraudulent certificates and subsequently removed from the registry.

Until recently, falsely flagged ships routinely flouted maritime laws while still relying on the “right of innocent passage” established under international convention.

While the U.S. hasn’t publicly explained the legal basis for boarding and seizing Skipper, Article 110 of the United Nations Convention on the Law of the Sea permits any authority to board vessels that are stateless or lack nationality.

Following this, the U.S. can apply its civil forfeiture warrant — a strategy used successfully in several cases since 2019 to seize oil and tankers linked to Iran.

U.S. officials have indicated more seizures are imminent. This comes amid the largest U.S. naval buildup in the Caribbean in decades, centered on Venezuela and increasing pressure on President Nicolás Maduro, whom the Trump administration has said should be removed from power.Any dark fleet tankers without a legitimate flag now loitering off Venezuela’s coast are likely the next targets in a rapidly evolving strategy aimed at constraining and disabling the dark fleet.