International Maritime Organization (IMO)
The United Nations agency that sets global rules for ship safety, security and pollution prevention.
- Category
- Regulation and Compliance
- Abbreviation
- IMO
- Dictionary entry
- IMO
- Last reviewed
How it works
The International Maritime Organization (IMO) is the UN specialised agency responsible for the safety and security of shipping and the prevention of marine and atmospheric pollution by ships. Its conventions (SOLAS, MARPOL, the Load Line and Tonnage conventions, and others) are the backbone of global maritime regulation.
The IMO also issues the seven-digit IMO ship identification number, a permanent identifier that stays with a hull for life regardless of flag or name changes, making it the anchor for vessel data and screening.
Where it shows up on The Maritime
Also known as: IMO, international maritime organization, IMO number.
The short dictionary definition is at Dictionary entry: IMO. This page is the explainer.
Related terms
MARPOL
The IMO convention preventing pollution from ships: oil, chemicals, sewage, garbage and air emissions, across six annexes.
Carbon Intensity Indicator (CII)
An IMO operational measure of how much CO₂ a ship emits per unit of transport work, graded A to E each year.
Energy Efficiency Existing Ship Index (EEXI)
A one-time IMO design-efficiency standard that existing ships must meet, the in-service counterpart of the EEDI for new ships.
Port State Control (PSC)
The inspection of foreign ships in national ports to verify they meet international safety and environmental standards.
Flag State
The country in which a ship is registered, whose laws she sails under and which is responsible for her regulatory oversight.
More regulation and compliance terms
A plain-English reference definition: our own explanation of a standard shipping concept, not a licensed source or legal advice. See the full glossary or the broader maritime dictionary.
Last reviewed: .