Sanctions Evasion Reference

Flag state

The country in which a ship is registered, whose law governs the vessel and which is responsible for inspecting and certifying it.

reviewed

2026-08-20

Under the law of the sea, jurisdiction over a ship on the high seas belongs to its flag state. That state issues the certificates, sets the safety and crewing standards, and is responsible for enforcement against the vessel.

The whole architecture therefore depends on flag states doing the work. Where a registry has limited capacity, or is administered commercially from another country, the certificates continue to be issued while the supervision behind them does not exist.

Where this term is used

  • What is AIS manipulation and AIS spoofing? — Disabling a ship's position transponder, or transmitting false position data through it, so that the vessel's recorded track does not show where it actually went.
  • What is flag hopping? — Re-registering a ship repeatedly between flag states, often to registries with limited oversight, so that its regulatory history is broken and its documented identity keeps changing.
  • What is opaque marine insurance? — Presenting protection and indemnity or hull cover from a provider that cannot be identified, or whose ability to meet a claim cannot be established, in order to satisfy a requirement to be insured.
  • What is a ship-to-ship transfer? — Transferring cargo directly between two vessels at sea, rather than through a port, so that the cargo changes hands where there is no port authority, no customs entry and no independent record.

Related terms

  • Flag of convenience — Registration of a ship in a state with which its owners have no genuine connection, chosen for cost, tax or regulatory reasons.
  • Open registry — A ship registry that accepts vessels owned by foreign nationals without requiring a national ownership or crewing link.
  • Zombie registry — A ship registry that continues to issue documentation in a state's name after that state has withdrawn authorisation, or that never had it.
  • IMO number — A seven-digit identifier assigned to a ship's hull for life by the International Maritime Organization, which does not change with name, owner or flag.

Sources

  1. Guidance to Address Illicit Shipping and Sanctions Evasion Practices. U.S. Department of State, U.S. Department of the Treasury and U.S. Coast Guard, 2020. Global maritime advisory, 14 May 2020.

All glossary terms