Sanctions Evasion Reference

Ship-to-ship transfer

Transferring cargo directly between two vessels at sea or at anchorage rather than through a port terminal.

also known as

STS transfer, lightering

reviewed

2026-08-20

Ship-to-ship transfer is a routine commercial operation used for lightering, for reaching ports with draught limits, and for consolidating parcels. Done normally it is announced, insured, logged and conducted in designated areas in daylight.

The 2020 global advisory issued by State, Treasury and the Coast Guard describes its abuse in detail: transfers at night, in poor weather, outside recognised areas, and with vessels whose identity cannot be established. Because the cargo changes hands where there is no port authority, it is also the point at which the documented origin of a cargo can be replaced.

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 cargo origin blending? — Mixing, decanting or re-documenting a commodity in transit so that restricted cargo is no longer traceable to its origin and arrives certified as coming from somewhere else.
  • 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

  • Automatic Identification System — A mandatory maritime transponder system that broadcasts a vessel's identity, position, course and speed to nearby vessels and shore stations.
  • Shadow fleet — A loosely defined group of ageing tankers with opaque ownership and insurance that carry sanctioned or price-capped cargo outside mainstream shipping arrangements.

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.
  2. Syria Shipping Advisory: Sanctions Risks Related to Petroleum Shipments to Syria. U.S. Department of the Treasury, Office of Foreign Assets Control, 2019.

All glossary terms