An interesting sanctions topic, from a regulatory standpoint, but not so much from an operational standpoint – for all but the firms with the largest exposures (and with active documentary credit or marine insurance business lines), while they might leverage third party data, I highly doubt they will do the kind of active vessel tracking as listed below:

While the term “shadow fleet” (often used interchangeably with “dark fleet”) is most frequently associated with Russia, Iran, and Venezuela, it does not refer to a formal navy belonging to any single nation. Instead, it is a decentralized, “stateless” network of aging merchant vessels—primarily oil tankers—that operate outside standard maritime regulations to evade international sanctions.

Based on reports from late 2024 through 2025, here is the breakdown of the nations involved, how these vessels are identified, and by whom.

1. Which Nations Have a “Shadow Fleet”?

These three nations are the primary drivers of the shadow fleet, utilizing it to export sanctioned commodities (mostly crude oil, LNG, and refined products) to willing buyers in countries like China and India.

• Russia: Currently operates the largest shadow fleet, estimated to include approximately 600–1,000 vessels. Following the G7 price cap on Russian oil, Moscow aggressively acquired aging tankers to bypass Western insurance and shipping services.
• Iran: Has utilized a “ghost fleet” for decades to evade US sanctions. Their network is highly sophisticated, often specializing in ship-to-ship (STS) transfers in locations like the Strait of Malacca or the Persian Gulf to disguise the origin of their oil.
• Venezuela: Relies on a similar, though often smaller and more dilapidated, fleet to export oil (primarily to Asia) in defiance of US sanctions on its state oil company, PDVSA.

Note on Interconnectedness: Recent intelligence suggests these fleets are no longer distinct. They have evolved into an “interwoven” network where vessels may transport Russian oil on one voyage and Iranian or Venezuelan cargo on the next, sharing the same illicit maritime infrastructure and shell company networks.

2. How Are They Identified?

Identifying these vessels requires a “multi-sensor” approach because they actively employ deceptive shipping practices (DSP). Authorities and intelligence firms use a combination of the following methods:

• AIS “Spoofing” Detection:
  • The Tactic: Vessels disable their Automatic Identification System (AIS) transponders (“going dark”) or use software to broadcast a fake location. For example, a ship physically loading oil in a Russian port may appear on digital maps to be sailing in the middle of the Atlantic.
  • The Counter-Measure: Analysts use algorithms to detect “AIS gaps” (periods of silence) or “impossible jumps” where a ship’s signal moves faster than physically possible.
• Satellite Imagery & Remote Sensing:
  • Visual Confirmation: Optical satellites and Synthetic Aperture Radar (SAR) are used to “see” vessels through clouds and at night.
  • The Match: Analysts compare the satellite image of a vessel’s physical location against its broadcast AIS location. If a ship is seen via satellite at a restricted terminal while its AIS signal claims it is elsewhere, it is flagged as a spoofer.
• Behavioral Analysis (The “Gray Fleet”):
  • Rather than hard evidence of a specific violation, analysts look for “abnormal” behaviors. This includes loitering in known trans-shipment zones (like the waters off Greece or Malaysia), frequent changes of ownership (often to shell companies in the UAE or Hong Kong), or “flag hopping” (frequently registering the ship in different high-risk jurisdictions).
• Document & Insurance Verification:
  • Compliance officers check if a vessel has legitimate P&I (Protection and Indemnity) insurance from a reputable Western club. Shadow vessels often lack this or carry dubious insurance that would not provide coverage in the event of an oil spill.

3. Who Identifies Them?

The identification is a collaborative effort between government enforcers and private intelligence firms who sell their data to governments, banks, and traders.

Government & International Bodies

• OFAC (USA): The Office of Foreign Assets Control uses classified intelligence and public data to formally “designate” (sanction) specific vessels and their owners.
• OFSI (UK) & European Commission: Similar to OFAC, these bodies track and list vessels banned from entering UK/EU ports or accessing maritime services.
• The “Shadow Fleet Coalition”: A group of nations (including the UK, Denmark, Estonia, Finland, Poland, and Sweden) formed specifically to share intelligence on these vessels, particularly regarding environmental risks in the Baltic Sea.

Private Sector & Intelligence Firms

• Maritime AI Companies: Firms like Windward, Kpler, Vortexa, and Lloyd’s List Intelligence are the primary “detectives.” They use AI to process millions of data points and sell “risk alerts” to banks and insurers.
• NGOs & Non-Profits: Organizations like Global Fishing Watch and SkyTruth use public satellite data to expose dark vessels, often focusing on environmental risks (e.g., oil spills from decrepit shadow tankers).
• Academic Institutes: Think tanks like the Kyiv School of Economics (KSE) and RUSI (Royal United Services Institute) regularly publish detailed reports naming specific vessels and analyzing the fleet’s size.

Summary of Key Identifiers (2024-2025 Context)

Indicator	Legitimate Fleet	Shadow / Dark Fleet
Ownership	Transparent; known major shipping lines	Opaque; shell companies in Seychelles, UAE, Hong Kong
Insurance	International Group of P&I Clubs (High coverage)	Unknown or “Shadow” insurers (Low/No coverage)
Flag State	Marshall Islands, Liberia, Panama (Tier 1)	Gabon, Cameroon, Cook Islands, Eswatini (High risk)
AIS Signal	Always On; Accurate	Frequently Off; Spoofed (Fake location)
Age	Typically <15 years	Typically >18-20 years (End of life)

Sources

• Atlantic Council (atlanticcouncil.org)
• Brookings Institution (brookings.edu)
• European Commission (finance.ec.europa.eu)
• Global Fishing Watch (globalfishingwatch.org)
• Kpler (kpler.com)
• Kyiv School of Economics (KSE) (sanctions.kse.ua)
• Lloyd’s List Intelligence (https://www.google.com/search?q=lloydslistintelligence.com)
• Pole Star Global (polestarglobal.com)
• Royal United Services Institute (RUSI) (rusi.org)
• SkyFi (skyfi.com)
• SkyTruth (skytruth.org)
• U.S. Department of the Treasury (OFAC) (home.treasury.gov)
• Ukrainian Defense Intelligence (war-sanctions.gur.gov.ua)
• Windward AI (windward.ai)