Fact Sheet

The IMO Number Explained

IMO number

© Adam Baske

What is an IMO number?

The International Maritime Organization (IMO) introduced its Ship Identification Number Scheme in 1987 to help prevent maritime fraud and enhance the security of merchant vessels. It is recognized by regional fisheries organizations and most governments and is considered the best available global identification system for ships. IHS Maritime & Trade, a company based in the U.K., administers the scheme on behalf of the IMO. The unique seven-digit vessel number the company issues to each vessel, preceded by the letters IMO, stays with it until it is scrapped and never changes, regardless of the ship’s owner, country of registration or name. The records based on the IMO number provide an independent audit trail for each vessel. The scheme was applied to fishing vessels in 2013, and the eligibility criteria were amended in 2016 to cover smaller and non-steel hull vessels.

Why do fishing vessels need an IMO number?

Illegal, unreported, and unregulated fishing worldwide accounts for up to 26 million metric tons of fish annually, worth up to $23.5 billion. IMO numbers are an essential tool in the fight against illegal fishing because they help to improve monitoring, control, surveillance and enforcement of fishing operations. They:

  • Allow flag States to accurately manage vessels under their authority.
  • Give national authorities information to help them police their waters more effectively.
  • Bring clarity and consistency to Regional Fisheries Management Organization (RFMO) records, helping governments determine whether vessels are authorized to fish in their waters.
  • Help port authorities ensure that they are accepting only legally caught fish, a requirement of the United Nations Food and Agriculture Organization’s Port State Measures Agreement.
  • Give retailers and seafood buyers a way to identify the vessels catching and landing their fish.

Since fishing vessels became eligible to apply for IMO numbers in 2013, many major RFMOs and other fisheries bodies, the European Union and some coastal and flag States have mandated that vessels above a certain size or tonnage must carry one. It is therefore becoming increasingly important to obtain one if vessels want to fish in these areas. As more organizations and States require the IMO number, the areas at sea in which vessels can legally fish without one will shrink.

Having an IMO number could also make exports more attractive, and an increasing number of retailers have made an IMO number a requirement for vessels they purchase fish from.

Since fishing vessels became eligible to apply for IMO numbers in 2013, many major RFMOs and other fisheries bodies, the European Union and some coastal and flag States have mandated that vessels above a certain size or tonnage must carry one.

Which vessels are eligible for an IMO number?

Any fishing vessel, refrigerated cargo vessel (reefer) or supply vessel 12 meters in length or above, authorized to operate outside waters of national jurisdiction (within an RFMO or another country’s 200-mile exclusive economic zone), and including those with a non-steel hull construction, is eligible for an IMO number. Any fishing vessel over 100 gross tons (GT) is also eligible for an IMO number, including those not authorized to operate outside their country’s jurisdiction. For further information, please see the following chart:

IMO number
IMO number
IMO number

The crew of a fishing vessel paints a new name on the hull at sea in an effort to avoid enforcement for crimes committed under a prior name. Mandatory IMO numbers would make vessels easier to positively identify. The unique seven-digit vessel number the company issues to each vessel, preceded by the letters IMO, stays with it until it is scrapped and never changes, regardless of the ship’s owner, country of registration or name.

© Australian Fisheries Management Authority

Will I have to pay?

No. Obtaining an IMO number is free.

How do I obtain an IMO number?

As an owner of a single vessel:

Applications can be made online at http://imonumbers.ihs.com using the free registration system, or you can download a form and send it to IHS Maritime & Trade at the following address:

IHS Maritime & Trade
Sentinel House
163 Brighton Road
Coulsdon
Surrey
CR5 2YH
United Kingdom
Email: ship.imo@ihs.com
Telephone: +44 (0)1344 328300

As a flag State for multiple vessels:

It may be easier as a flag State to apply for IMO numbers for multiple vessels on your registry at one time. It will give you more control and will ensure more accurate records. Should you require this, contact the IHS Maritime & Trade IMO Ship Numbering Department at ship.imo@ihs.com for a multiple IMO request form in spreadsheet format.

Where should I display my IMO number?

Seagoing vessels of 100 GT and above are required to display identification numbers clearly and permanently in a visible place, either on the vessel’s hull or superstructure. The IMO number should be inserted on a vessel’s Certificate of Registry, which includes information identifying the vessel, and on all certificates issued under IMO Conventions when and where appropriate. Pew, along with Trygg Mat Tracking, an organization specializing in fisheries intelligence analysis, recommends that companies also include the number in other certificates, such as classification certificates, when and where appropriate. It should preferably be included in the box headed “Distinctive number or letters” in addition to the call sign.

Fishing vessels may mark the IMO number either on the stern or stern quarter with the name and port, avoiding the part of the hull where nets may obscure them. Alternatively, vessels may display the number on the hull or superstructure sides, with the call sign and/or fishing number. Fishing vessels should also insert the IMO number on the certificates outlined above, as is required for large seagoing vessels. Your flag administration or class society can provide further guidance for displaying IMO numbers.

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