Registration of a ship plays an imperative function towards safety and security of the maritime transport and significantly contributes towards the protection and preservation of the marine environment.
The general mechanism for establishing a ship's nationality and for regulating shipping is registration of the ship in a particular State. By linking a ship to a State, the system of ship registration indicates that that State has the right to protect that ship in international law.
A core principle in public international law is the freedom of the high seas, as laid out in article 87 of UNCLOS. To balance this freedom with the need to avoid disorder and misuse, international law has provided a framework for the regulation of shipping. This framework rests upon two core rules:
- each State shall fix the conditions for the grant of its nationality to ships, for the registration of ships in its territory, and for the right to fly its flag (article 91 of UNCLOS); and
- the State must effectively exercise its jurisdiction and control in administrative, technical and social matters over ships flying its flag (article 94 of UNCLOS).
Article 91(1) of UNCLOS acknowledges the right of every State to "fix the conditions for the grant of nationality and for the right to fly its flag." The same article provides that there "must exist a genuine link between the State and the ship." The purpose of the "genuine link" requirement in UNCLOS is to secure more effective implementation of the duties of the flag State under article 94 of UNCLOS.
There is currently no binding international framework to regulate the registration process itself. The 1986 UN Convention on Conditions for Registration of Ships establishes international standards for the registration of vessels in a national registry, including references to the genuine link, ownership, management, registration, accountability and the role of the flag State. However, the Convention has not entered into force.
Open registry/closed registry
Each country sets its own laws and regulations on the registration of ships . Some countries only register vessels with ties to the country through ownership or crewing ("closed registries"). Other countries allow foreign-owned or controlled vessels to use their flag through an "open registry." Others just choose not to allow the use of their flag for international trade at all.
Since open registries are now widely used around the world, IMO has focused on a strategic approach to ensuring that flag States adequately assume jurisdiction and control over shipowners and ships that are flying their flags in accordance with article 94 of UNCLOS.
IMO initiatives with regards to strengthening flag State and port State jurisdiction and control
IMO has adopted and implemented a number of measures to support and enhance flag (and port) State jurisdiction and enforcement. These include:
IMO Member State Audit Scheme;
IMO Ship Identification Number Scheme and IMO Unique Company and Registered Owner Identification Number Scheme : these two schemes have been made mandatory under SOLAS regulation XI-1/3 and XI-1/3-1, respectively (Link to IMO webpage);
continuous Synopsis Record (CSR): security-related requirements;
Cape Town Agreement of 2012 and the STCW-F Convention: flag State responsibilities in relation to fishing vessels and fishers;
collection of data: the Port State Control (PSC) module in GISIS aims at improving transparency and accountability with respect to standards on ships and fishing vessels;
work of the Sub-Committee on Implementation of IMO Instruments (III); and
IMO/ILO work on seafarer issues: database on abandoned vessels created by the Joint ILO/IMO Ad Hoc Expert Working Group on Liability and Compensation Regarding Claims for Death, Personal Injury and Abandonment of Seafarers.
In July 2005, an ad hoc Consultative Meeting of Senior Representatives of International Organizations on the "Genuine Link" highlighted the obligations imposed upon flag States by UNCLOS. The meeting stressed the need to strengthen flag State jurisdiction and highlighted the subsequent improvement in flag States' enforcement of their international legal obligations as a result of the work of IMO.
Fraudulent registration and fraudulent registries of ships
Fraudulent registration and related unlawful practices include the registration of vessels without the knowledge or approval of the relevant national maritime administration. Such fraudulent registrations are accomplished through a combination of tactics that may include the following:
Terminated registry: where a vessel, formerly entitled to fly the flag of a given State, continues to fly that flag after the vessel's registration with the flag State has expired or has otherwise been terminated.
Fraudulent representations to IMO: the submission of fraudulent documentation to IMO, without the knowledge of the cognizant flag State authority, in order to obtain IMO documentation and ship identification numbers. Fraudulent registration companies may operate with authentic‑looking websites and claim to be the official registration offices authorized to grant to ships the nationality of the State concerned.
Broadcasting falsified Automatic Identification System (AIS) data: this tactic involves the intentional manipulation of AIS data to materially alter the ship's identifying information or to reflect the AIS data of an entirely different vessel.
Legal Committee work on fraudulent registration of ships and fraudulent operation of registries
The problem of fraudulent registration of ships and fraudulent operation of registries was first raised at IMO by the Democratic Republic of the Congo (DRC) in 2017 during the 104th session of the Legal Committee. The DRC reported that approximately 73 vessels had been fraudulently using its flag and that illegal fishing was being carried out in its waters to its economic detriment.
Fraudulent registration of ships prevents lawful registries from exercising effective jurisdiction and control over vessels at sea, deprives lawful registries from obtaining legitimate revenue while unjustly enriching fraudulent actors and exacts unjustified reputational harms on States when vessels engage in illicit activities under the cloak of a fraudulent registration. Furthermore, fraudulently registered ships may not be in compliance with safety and environmental protection standards, endangering the vessels' crew and posing an increased threat of damage to the marine environment.
In 2018, the Legal Committee recognized the need for a multi-pronged approach and that the solution would involve making accurate information about the status of a nation's registry widely, quickly and accurately available to shipowners and insurers, as well as public officials. Following that (Link to the IMO webpage, LEG summary), the Secretariat reported on several cases related to the fraudulent use of a country's flag, and/or to the fraudulent operation of a registry without the purported flag country's permission or knowledge. These cases concerned, in addition to DRC, the Federated States of Micronesia, Fiji, the Maldives, Nauru, Samoa, the United Republic of Tanzania and Vanuatu. 
The Secretariat has been studying the cases received reporting on fraudulent use of a flag or of a registry and collaborating with IHS Markit to improve the display in GISIS of information on a ship which was confirmed by an Administration as not legally registered under that Administration's flag.
Enhancing contact points database
Following the 106th session of the Legal Committee, in 2019, the Secretariat has developed a new function in the Contact Points module in GISIS that would be a comprehensive database of registries of ships, where information for all flags could be available in one place. The Committee also agreed that IMO should work with the UN Security Council to establish an easily searchable database, by IMO number and vessel name, of vessels currently the subject of, or designated pursuant to, UNSC resolutions.
IMO has also taken steps to thoroughly review the authenticity of requests to access IMO web accounts.
Resolution - Measures to prevent the fraudulent registration and fraudulent registries of ships
In order to establish even more robust procedures for the communication of information to IMO, the Assembly adopted a resolution on Measures to prevent the fraudulent registration and fraudulent registries of ships (A.1142(31)).
The Assembly resolution includes a procedure for communicating information on ship registries to IMO, including information on the name of national governmental body(ies) and authorized or delegated entities in charge of ship registration. Its aim is to allow the IMO Secretariat to verify the information, through the appropriate channels
Recommended best practices
The Committee has also approved a LEG circular on Recommended best practices to assist in combating fraudulent registration and fraudulent registries (LEG.1/Circ.10).
 According to the International Tribunal on the Law of the Sea (ITLOS) in the 1999 case, M/V Saiga (No. 2).
 The Convention requires 40 signatories whose combined tonnage exceeds 25% of the world total. As of March 2020, fifteen States had ratified or acceded to the Convention (Albania, Bulgaria, Côte d'Ivoire, Egypt, Georgia, Ghana, Haiti, Hungary, Iraq, Liberia, Libya, Mexico, Morocco, Oman, and Syria) and the Convention had been signed, subject to ratification, acceptance, or approval, by further nine States (Algeria, Bolivia, Cameroon, Czech Republic, Indonesia, Poland, Russian Federation, Senegal, and Slovakia).
 See Nigel P Ready, Nationality, Registration, and Ownership of Ships in The IMLI Manual on International Maritime Law: Volume II: Shipping Law.
 A.1078(28), IMO ship identification number scheme.
 MSC.160(78), Adoption of the IMO unique company and registered owner identification number scheme.
 A.923(22), Measures to prevent the registration of "phantom" ships.
 The report of the Meeting was forwarded to the United Nations Secretary-General in pursuance of United Nations General Assembly resolutions 59/24 and 59/25 and subsequently submitted to the General Assembly at its 61st session (A/61/160).
 Documents LEG 106/7 and LEG 106/7/Add.1 and Circular Letter Nos.3717, 3798, 3840 and 3855.
 In such a case, a "false flag" for the particular ship is shown in the module on Ship and company particulars in GISIS. This status would change as and when the ship would be registered under a new flag.