As Washington debates U.S. authority on the high seas amid escalating maritime standoffs, the rise of ghost fleets is making headlines. Their spread has pushed the International Maritime Organization into the spotlight – and underscores why U.S. engagement in the very institutions that manage risk matters long before disputes spill into open conflict.
Also known as shadow ships or dark fleets, these vessels bypass maritime rules and international sanctions, most often tied to oil, though human trafficking and other illicit trade are close behind. Russia, Venezuela and Iran feature prominently in these operations, using regulatory gaps to operate in plain sight while avoiding accountability.
Here’s how these dark vessels operate, why it matters to Americans and IMO’s essential role at the center of the response.
Events unfolding in America’s backyard make clear that U.S. engagement in IMO is neither abstract nor symbolic; it helps determine whether disputes are managed through rules and coordination, or left to escalate.
Who Writes the Rules
Considered a technical agency of the United Nations, IMO is where global standards for maritime safety, security and pollution are negotiated and enforced. In 2023, IMO formally defined dark fleet practices, underscoring the growing risks posed by vessels that operate outside established norms.
Those definitions draw largely from the UN Convention on the Law of the Sea (UNCLOS), which sits within the UN Division for Ocean Affairs. Although a core principle of UNCLOS is freedom of the high seas (Article 87), that right is balanced by rules that require ships to meet safety and environmental standards, register under a national flag, continuously broadcast their precise location, carry insurance and more.
Where the system weakens is not in the rules themselves, but enforcement. That’s because the UN principle of sovereignty leaves some of the finer points to individual states, like how fraudulent registrations are prosecuted. This creates space for less scrupulous actors to exploit loopholes.
It’s important to note that the U.S. is among roughly two dozen countries that have not formally ratified UNCLOS, though Senate support is strong and U.S. naval operations and domestic maritime law largely align with its provisions. Ratification would strengthen U.S. legal standing to challenge ghost fleets and give Washington greater leverage to shape enforcement norms and close loopholes.
How Ghost Ships Disappear
There are a number of familiar tactics these nefarious fleets use to obscure their ownership, cargo, financing, routes and destinations.
First, many vessels turn off or manipulate 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. “AIS spoofing,” for example, was employed by a ship in the Caribbean during a high-profile case in December.
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, a common practice by Russia. 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 workarounds, these transfers also create significant safety risks, especially when conducted by older, poorly maintained tankers far from regulators.
To remain 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. According to analysis from the Center for Strategic and International Studies, 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.
How Do 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.
A U.S.-UN Issue
For more than half a century, the U.S. has helped lead the UN’s technical agencies, including IMO, where rules addressing global challenges like ghost fleets and sanctions accountability are set. In fact, America’s own Coast Guard has been central to that effort, participating in “all policy development” since IMO’s founding. In addition, advisors to IMO have hailed from the U.S. Department of State, Homeland Security, Defense, Justice, the Environmental Protection Agency, National Oceanic and Atmospheric Administration and National Transportation Safety Board. Much of what the world now considers international maritime law bears a distinctly American imprint.
That record is worth recalling as Congress weighs support for the UN. Events unfolding in America’s own backyard make clear that U.S. engagement in institutions like IMO is neither abstract nor symbolic. It helps determine whether disputes are managed through rules and coordination, or left to escalate through miscalculation and force. It also ensures that adversaries who engage in practices like the use of dark fleets reap consequences not only from the U.S., but from the global community.
In an era of rising maritime risks, sustained U.S. leadership remains one of the most effective, least costly ways to protect American interests – without firing a shot.
In an era of rising maritime risks, sustained U.S. leadership remains one of the most effective, least costly ways to protect American interests – without firing a shot.
