IMOnummer

IMOnummeren, or IMO number, is a unique seven-digit identifier assigned by the International Maritime Organization to ships. In practice, the term refers to the ship identification number used internationally to identify a vessel throughout its life, regardless of name, flag, or ownership changes. There is also a separate concept called the IMO Company Number, which identifies shipping companies and managers, but this is distinct from the ship’s IMO number.

The IMO number is intended to provide a stable, internationally recognized reference for ships. It is usually assigned when a vessel is first registered or entered into the IMO’s systems and remains associated with the vessel for its entire life. Because the number does not change with changes in ownership, flag state, or name, it facilitates tracking, safety, and regulatory enforcement across registries and databases.

Displaying and usage: The IMO number is typically recorded in official ship documents such as the certificate of registry and safety certificates, and it is often painted on the hull or displayed near the bow or superstructure for ease of identification. Industry and authorities use the number in port state control, inspections, safety records, insurance, and data reporting. It also serves as a key identifier in databases like GISIS and Equasis.

Relation to other identifiers: The IMO number is distinct from maritime radio identifiers such as MMSI, which are used for communications. The IMO Company Number, when used, identifies the owning or managing company rather than a specific vessel.

Access: Public databases and registries, including GISIS and Equasis, allow searching by IMO number to retrieve vessel information and history.