The International Maritime Organization (IMO; , , OMI) is a specialized agency of the United Nations regulating maritime transport. It was established following agreement at a UN conference held in Geneva in 1948, but it did not come into force for ten years until the new body, then called the Inter-governmental Maritime Consultative Organization, first assembled on 6 January 1959. Headquartered in London, United Kingdom, the IMO has 176 Member States and three Associate Members as of 2025.
The IMO's purpose is to develop and maintain a comprehensive regulatory framework for shipping. Its remit includes maritime safety, environmental concerns, and legal matters. IMO is governed by an assembly of members which meets every two years. Its finance and organization is administered by a council of 40 members elected from the assembly. The work of IMO is conducted through five committees supported by technical subcommittees. Other UN organizations may observe the proceedings of the IMO. Observer status is granted to qualified NGOs.
IMO is supported by a permanent secretariat of employees who are representative of the organization's members. The secretariat is composed of a Secretary-General elected by the assembly, and various divisions such as those for marine safety, environmental protection and a conference section.
History
In February–March 1948 the United Nations Maritime Conference in Geneva institutionalized the regulation of the safety of shipping into an international framework. Hitherto such international conventions had been initiated piecemeal, notably the Safety of Life at Sea Convention (SOLAS), adopted in 1914 following the Titanic disaster. The conference resolved "that an international organization to be known as the Intergovernmental Maritime Consultative Organization shall be established"; however many countries did not trust the convention, so ratification was slow and it took until March 1958 until it came into force.
The Inter-Governmental Maritime Consultative Organization (IMCO; now using the hyphen) held its first Assembly in London in January 1959. Its initial task was to update the SOLAS; the resulting 1960 International Convention for the Safety of Life at Sea was recast in 1974 and subsequently modified and updated to adapt to changes in safety requirements and technology. Since 1978, every last Thursday of September has been celebrated as World Maritime Day.
When IMCO began its operations in 1959 certain other pre-existing conventions were brought under its aegis, most notably the International Convention for the Prevention of Pollution of the Sea by Oil (OILPOL) from 1954. Under the guidance of IMCO, the convention was amended in 1962, 1969, and 1971.
As oil trade and industry developed, many people in the industry saw a need for further improvements in regards to pollution prevention. This became increasingly apparent in 1967, when the tanker Torrey Canyon ran aground entering the English Channel and spilled record-breaking 120,000 tons of crude oil. This incident prompted a series of new conventions.
IMO held an emergency session of its council to deal with the need to readdress regulations pertaining to maritime pollution. In 1969, the IMO Assembly decided to host an international gathering in 1973 dedicated to this issue. The goal was to develop an international agreement for controlling general environmental contamination by ships when out at sea. During the next few years IMO brought to the forefront a series of measures designed to prevent large ship accidents and to minimize their effects. It also detailed how to deal with the environmental threat caused by routine ship duties such as the cleaning of oil cargo tanks or the disposal of engine room wastes. By tonnage, the aforementioned was a bigger problem than accidental pollution. The most significant development to come out of this conference was the International Convention for the Prevention of Pollution from Ships, 1973 (MARPOL). It covers not only accidental and operational oil pollution but also different types of pollution by chemicals, goods in packaged form, sewage, garbage and air pollution. The original MARPOL was signed on 17 February 1973, but did not come into force due to lack of ratifications. The current convention is a combination of 1973 Convention and the 1978 Protocol. It entered into force on 2 October 1983. As of December 2025, 162 states, representing 98.89 per cent of the world's shipping tonnage, are signatories to the MARPOL convention.
As well as updates to MARPOL and SOLAS, the IMO facilitated several updated international maritime conventions, including the International Convention on Load Lines in 1966 (replacing an earlier 1930 Convention), the International Regulations for Preventing Collisions at Sea in 1972 (also replacing an earlier set of rules) and the STCW Convention in 1978. In 1975, the assembly of the IMO decided that future conventions of the International Convention for the Safety of Life at Sea (SOLAS) and other IMO instruments should use SI units. Sea transportation is one of few industrial areas that still commonly uses non-metric units such as the nautical mile (nmi) for distance and knots (kn) for speed or velocity.One nautical mile is approximately one minute of arc of latitude along any meridian arc, and defined since 1929 as precisely 1852 meters (about 1.151 statute miles). In November 1975, the IMCO Assembly, as a part of comprehensive review of the Convention, decided to rename it as the International Maritime Organization (IMO); after ratifications, this happened in May 1982. Throughout its existence, the IMO has continued to produce new and updated conventions across a wide range of maritime issues covering not only safety of life and marine pollution but also encompassing safe navigation, search and rescue, wreck removal, tonnage measurement, liability and compensation, ship recycling, the training and certification of seafarers, and piracy. More recently SOLAS has been amended to bring an increased focus on maritime security through the International Ship and Port Facility Security (ISPS) Code. The IMO has also increased its focus on smoke emissions from ships. In 1983, the IMO established the World Maritime University in Malmö, Sweden and also facilitated the adoption of the IGC Code. In 1991, the IMO facilitated the adoption of the International Grain Code.
In December 2002, the IMO adopted the International Ship and Port Facility Security Code (ISPS) Code as part of amendments to the 1974 SOLAS Convention. The code entered into force under SOLAS chapter XI-2 on 1 July 2004 and established a mandatory security regime for international shipping, including requirements for ship and port facility security plans.
On 1 January 2017, the IMO introduced a new mandatory International Code for Ships Operating in Polar Waters (Polar Code), covering shipping operations in the polar regions of Earth.
In 2025, the IMO updated its logo to all six official UN languages (Arabic, Chinese, English, French, Russian, Spanish). Headquarters
The IMO headquarters is a large purpose-built building facing the River Thames on the Albert Embankment, in Lambeth, London. The organization moved into its new headquarters in late 1982, with the building being officially opened by Queen Elizabeth II on 17 May 1983. The architects of the building were Douglass Marriott, Worby & Robinson. The front of the building is dominated by a seven-metre high, ten-tonne bronze sculpture of the bow of a ship, with a lone seafarer maintaining a look-out. The previous headquarters of IMO were at 101 Piccadilly (now the home of the Embassy of Japan), prior to that at 22 Berners Street in Fitzrovia and originally in Chancery Lane.
Structure The IMO consists of an Assembly, a Council and five main Committees. The organization is led by a Secretary-General. A number of Sub-Committees support the work of the main technical committees.
Governance of IMO
The governing body of the International Maritime Organization is the Assembly which meets every two years. In between Assembly sessions a Council, consisting of 40 Member States elected by the Assembly, acts as the governing body. The technical work of the International Maritime Organization is carried out by a series of Committees. The Secretariat consists of some 300 international civil servants headed by a Secretary-General.
The Secretary-General Arsenio Dominguez took office for a four year term on 1 January 2024, having been elected in July 2023. The previous Secretary-General was Kitack Lim from South Korea elected for a four-year term at the 114th session of the IMO Council in June 2015 and at the 29th session of the IMO's Assembly in November 2015. His mandate started on 1 January 2016. At the 31st session of the Assembly in 2019 he was re-appointed for a second term, ending on 31 December 2023.Personal Page of the Secretary-General , accessed: 9 July 2020Press-Briefing "Positional changes at IMO Secretariat" , accessed: 30 January 2012
Name Country Term Ove Nielsen Denmark 1959–1961† William Grahamacting, following Nielsen's death United Kingdom 1961–1963 Jean Roullier France 1964-1967 Colin Goad United Kingdom 1968-1973 Chandrika Prasad Srivastava India 1974-1989 William A. O'Neil Canada 1990-2003 Efthymios Mitropoulos Greece 2004-2011 Koji Sekimizu Japan 2012-2015 Kitack Lim South Korea 2016–2023 Arsenio Dominguez Panama 2024–present
Technical committees
The technical work of the International Maritime Organization is carried out by five principal Committees: The Maritime Safety Committee (MSC) The Marine Environment Protection Committee (MEPC) The Legal Committee The Technical Cooperation Committee, for capacity building The Facilitation Committee, to simplify the documentation and formalities required in international shipping. The Committees meet once or twice a year attended by Member States and NGOs.
Maritime Safety Committee It is regulated in the Article 28(a) of the Convention on the IMO:
The Maritime Safety Committee is the most senior of these and is the main Technical Committee; it oversees the work of its nine sub-committees and initiates new topics. One broad topic it deals with is the effect of the human element on casualties; this work has been put to all of the sub-committees, but meanwhile, the Maritime Safety Committee has developed a code for the management of ships which will ensure that agreed operational procedures are in place and followed by the ship and shore-side staff.
Sub-committees The MSC and MEPC are assisted in their work by a number of sub-committees which are open to all Member States. The committees are:
Sub-Committee on Human Element, Training and Watchkeeping (HTW) Sub-Committee on Implementation of IMO Instruments (III) Sub-Committee on Navigation, Communications and Search and Rescue (NCSR) Sub-Committee on Pollution Prevention and Response (PPR) Sub-Committee on Ship Design and Construction (SDC) Sub-Committee on Ship Systems and Equipment (SSE) Sub-Committee on Carriage of Cargoes and Containers (CCC).
The names of the IMO sub-committees were changed in 2013. Prior to 2013 there were nine Sub-Committees as follows:
Bulk Liquids and Gases (BLG) Carriage of Dangerous Goods, Solid Cargoes and Containers(DSC) Fire Protection (FP) Radio-communications and Search and Rescue (COMSAR) Safety of Navigation (NAV) Ship Design and Equipment (DE) Stability and Load Lines and Fishing Vessels Safety (SLF) Standards of Training and Watchkeeping (STW) Flag State Implementation (FSI)
Membership