In recent weeks, high-profile maritime standoffs have ignited debate in Washington about America’s reach on the high seas.
But beneath the surface, another story is making waves: the rise of ghost fleets.
As tensions escalate in the Caribbean, these dark ships are moving from maritime obscurity to the front pages – and spotlighting the quiet but critical role of the International Maritime Organization (IMO).
Here’s how ghost fleets operate, why they matter and how U.S. engagement in IMO through the United Nations can help turn the tide.
How Ghost Ships are Defined – and Disappear
Often referred to as dark fleets, ghost vessels or shadow ships, these vessels are commonly used to bypass maritime rules and international sanctions, most frequently those tied to oil (though human trafficking is not far behind). Russia, Venezuela and Iran feature prominently in discussions of these practices.
Ships of this kind are operated “off the books,” using a familiar set of tactics to obscure their ownership, cargo, financing, routes and destinations.
Many vessels do so by turning off or manipulating their Automatic Identification System (AIS), the required tracking signal that broadcasts identity and location. When AIS goes dark, ships vanish from maritime maps. When manipulated, vessels can appear to be sailing legally in international waters while actually slipping into sovereign seas, conducting covert transfers or docking at sanctioned ports. For dark fleets, AIS manipulation is the difference between being monitored and being untouchable.
Another common tactic is flying under another nation’s flag, often through so-called “flags of convenience” (FOC). By international law, every ship must be registered to a country, what’s known as its “flag state,” which is legally responsible for enforcing safety, labor and environmental rules. Dark fleet operators exploit this system by registering vessels in countries with limited enforcement capacity or by frequently switching flags to blur accountability. In more extreme cases, ships engage in “false-flag behavior,” deliberately misrepresenting their nationality or ownership – a serious violation of international norms designed to frustrate enforcement and shift blame away from the real operators.
Dark fleets also rely heavily on ship-to-ship transfers at sea to disguise cargo origins. Instead of docking at port, oil, for example, is transferred between vessels in open water, usually while the AIS is disabled. By mixing cargo mid-ocean, ships can erase the paper trail of sanctioned oil before it ever reaches land. Beyond the obvious sanctions workaround, these transfers also create serious safety risks, especially when conducted by older, poorly maintained tankers far from regulators.
Let’s stick with the topic of safety. To stay off authorities’ radar, most ghost ships avoid ports and inspections altogether. Ports are where vessels face paperwork checks, insurance verification and sanctions enforcement. Dark fleet vessels minimize port calls or rely on ports with weak oversight, allowing unsafe and illicit operations to continue unchecked for months or even years.
Finally, many ghost ships operate without insurance. Legitimate vessels carry coverage for oil spills, environmental damage and crew injuries. Ghost vessels often carry fraudulent certificates or no insurance at all. When accidents happen (spills, fires or collisions), there’s rarely an identifiable owner or financial backstop. That pushes clean-up costs onto coastal communities and taxpayers, turning illicit shipping into a public liability.
And if you think this crime is victimless, take the case of Ukraine. As analysis from the Center for Strategic and International Studies (CSIS) makes clear, Russia’s war in Ukraine is now heavily financed through these very operations. Since late 2022, Moscow has assembled a vast shadow fleet transporting an estimated 3.7 million barrels of oil per day, generating up to $100 billion annually – revenue that rivals the total value of U.S. assistance to Ukraine.
Who Writes the Rules
Fortunately, this is not a regulatory vacuum. Rules exist, many of which the U.S. helped to create. And with greater support, the rules and the bodies that support them could be further strengthened.
The International Maritime Organization (IMO) is where global standards for maritime safety, security and pollution prevention are negotiated and enforced. In 2023, IMO formally defined and addressed dark fleet practices, underscoring the growing risks posed by vessels that operate outside established norms.
The UN Convention on the Law of the Sea (UNCLOS) provides the legal framework that clarifies who is responsible for ships, what rights states have at sea and how deceptive practices like false flags, identity manipulation and stateless vessels are handled. UNCLOS is administered by the UN Division for Ocean Affairs and the Law of the Sea (DOALOS) as its Secretariat. (There are also specialized bodies like the International Seabed Authority (ISA) that reinforce and advise when nefarious maritime practices go even deeper.)
Although the U.S. has not formally ratified UNCLOS, U.S. naval operations and maritime law align closely with its provisions. That said, ratifying UNCLOS would buoy U.S. legal standing to challenge ghost fleets and shape enforcement norms.
A U.S.-UN Issue
Dark fleets thrive in the gaps between rules, coordination and enforcement – the same gaps now fueling tensions in the Caribbean. Sustained U.S. engagement in multilateral bodies and the legal frameworks they provide offers a lower-cost, lower-risk way to close those gaps, protect U.S. interests and reduce the risk that Caribbean flashpoints escalate – all without firing a shot.
6 Ways Ghost Fleets Impact Americans
They weaken sanctions and prolong conflicts. If sanctioned oil can still move, sanctioned regimes can still get paid.
They make global trade less transparent and more expensive. Illicit shipping increases scrutiny and costs for legitimate operators.
They increase the risk of oil spills. Aging, poorly maintained vessels operate outside normal inspection regimes.
They shift cleanup costs to coastal communities. When ownership and insurance are opaque, local economies pay the price.
They create collision risks at sea. AIS manipulation produces dangerous blind spots in busy shipping lanes.
They enable organized crime. The same secrecy that moves oil can move drugs, weapons or trafficked people.
