One Ship and Three Identities: What Is International Law Tracking?

[Bikashita Choudhury is a Research Associate with the Ocean Law and Policy team at the Centre for International Law (CIL), National University of Singapore]

When the United States (US) detained the ship Marinera in the Atlantic Ocean, it reported that it had been tracking the ship for weeks, noting its suspicious behaviour and probable involvement in illegal activities. US authorities mentioned that the ship loitered for months off the coast of Iran, where it turned off its  Automatic Identification System (AIS)- the digital system used to broadcast a ship’s location and identity- at least 17 times, continued to disappear from tracking systems while crossing the Strait of Malacca and the waters off Sri Lanka, eventually emerging with a different name. That raises a question: what was being tracked? And how? Was it the ship’s flag, its registered or documentary identity, satellite imagery of the ship, its physical appearance, or its AIS-transmitted data?

The United Nations Convention on the Law of the Sea (UNCLOS) was drafted around a ship’s flag, physically verifiable information, and registration, not real-time digital ship data. This distinction matters because a digital anomaly cannot, by itself, establish fraudulent registration, a ship without nationality, or an attempt to evade jurisdiction.

This post argues that, descriptively, ship identity fraud remains an unaddressed concept in legal scholarship and international frameworks. Enforcement practices have consequently treated all forms of identity manipulation as a single problem, most visibly demonstrated by the shadow fleet discourse. Fraudulent registration, AIS manipulation, and flag irregularities are collectively treated as indicators of illegal activity, obscuring their legally distinct character and the different regulatory regimes each engages.  Normatively, documentary ship identity, digital identity, and nationality are analytically and legally distinct; treating them otherwise would risk doctrinal distortion.

Ship Nationality and Ship Identity

Article 91 of UNCLOS enables States to establish the conditions for granting a ship their nationality. Ships that are granted nationality are issued registration documents based on domestic registration laws and are thereby entitled to fly the State’s flag. Nationality anchors a ship to its flag State, which exercises jurisdiction over it and maintains effective control over its administrative, social, and technical matters as required by Article 94.

By contrast, international law does not exhaustively define the constituents of a ship’s identity. UNCLOS leaves registration conditions to States while the International Maritime Organization (IMO) instruments address specific identity elements such as the ship’s name and its IMO number. In industry classifications, the IMO number, the name, the Maritime Mobile Service Identity (MMSI)- better understood as a unique radio calling number, the call sign, and vessel characteristics constitute a ship’s registered identity. Because these identity elements are not necessarily issued and regulated by the same authority or legal framework, this post uses the term “documentary identity” instead. Of these, the IMO number and vessel characteristics are permanent identifiers, while the name, flag, and MMSI are mutable. Since the flag further qualifies a ship’s nationality, it should constitute an element of ship identity, though industry classifications do not include it.

The difficulty arises on the open sea, when no one is close enough to read the ship’s hull, see its flag, or board it. In such circumstances, identification relies on data transmitted via the AIS. AIS transmits data corresponding to the industry-recognised components of the ship’s documentary identity. The industry refers to it as the digital identity. However, unlike documentary identity, it is self-reported and unverified at the point of origin. AIS may assist in identifying the ship; it does not conclusively establish its identity or nationality. Therefore, it is referred to here as ‘apparent digital identity’.

The MMSI, regulated by the International Telecommunication Union (ITU), contains an embedded country code. While operationally, the country code serves as an administrative affiliation and a proxy for nationality inference, the MMSI is not integrated into the UNCLOS nationality regime. Accordingly, a mismatch between the MMSI country code and the flag cannot, by itself, be treated as an interchange of flags under Article 92, nor justify the ship’s assimilation into statelessness for high seas enforcement purposes.

The Evolution of Identity Fraud

Identity fraud at sea predates the digital era. Historically, the ship’s name and its Lloyd’s Register number were both mutable. Ships would often change names, and the Lloyd’s Register number would change yearly, leaving a disconnect between the ship and its documents, especially when at sea. The MV Salem fraud of the 1980s highlights how this disconnect was abused. ‘South Sun’ was bought, renamed as ‘MV Salem’, and called into Durban port as ‘Lema’ before being deliberately sunk. Repeated name changes severed the ship’s documentary links, voyage history, port inspection records, and cargo details to avoid investigation and insurance scrutiny.

It was to prevent precisely such incidents that the IMO assigned a seven-digit permanent number for ships that followed the letters ‘IMO’. They remain permanent through a ship’s lifetime, resale, and renaming. Thereafter, the IMO made it compulsory under the Convention on Safety of Life at Sea (SOLAS) Chapter XI-1, Regulation 3, to engrave the ship’s IMO number on the ship to establish a connection between it and its issued documents.

Even then, fraud has been perpetrated by submitting false or inaccurate documentation to ship registries, resulting in the registration of phantom ships. The IMO has repeatedly urged States to exercise caution against the registration of phantom ships, even if accidental. The IMO’s 2002 Resolution A.923(22) specifically invited governments to review their ship registration practices to prevent registration of phantom ships. While fraud tactics evolved to target a ship’s records rather than the ship-document disconnect, such manipulations nonetheless impacted the documentary identity.

Recently, the IMO introduced guidelines on ship registration to eliminate registration-related fraud, indicating that attempts to tamper with various components of a ship’s identity are still ongoing.

In the era of apparent digital identity, the target is the AIS, which operates on the open-channel Very High Frequency (VHF) band over a limited range. Anyone with the required technology, including ships, coastal or port States, and some satellites, can receive AIS data. Therefore, if false information is transmitted through the manipulation of the AIS, multiple actors would receive incorrect information. The various types of AIS data tampering are collectively referred to as AIS manipulation.

Unlike traditional identity fraud, the AIS manipulation falsifies the information through which the ship’s digital identity is communicated. These fake IMO numbers and names, along with a manipulated MMSI, may or may not correspond with the ship’s documentary identity. While such conduct can be commercially labelled as apparent digital identity manipulation, the legal repercussions are uncertain, since communicated information does not itself constitute registration or nationality. 

Distinguishing Identity Frauds

Current discourses do not directly address the concept of identity fraud, nor the distinction between a ship’s documentary and apparent digital identities. The IMO Legal Committee, in its 108th session, discussed all these issues exclusively under the heading of fraudulent registration and was unable to reach a consensus on various definitions. Even questions related to identity manipulation beyond registration fraud were deferred. Working under significant time constraints and the pressure to address immediate enforcement concerns resulted in a missed opportunity to establish the foundational framework for a ship’s identity as a legal concept.

Fraudulent registration, mid-voyage identity manipulation, and communication manipulation may trigger differing legal consequences, evidentiary requirements, and jurisdictional responses. Yet these practices lack a coherent legal taxonomy. Qualifying them under a broad category or industry definition risks obscuring whether the issue is registration, nationality or merely manipulation of communicated information.

Registration fraud is State-specific and can only be verified by the registering State, leaving little room for third States to act. Nationality manipulation, if verified by the swapping of flags, engages Article 92, which assimilates such ships to ‘ships without nationality’, potentially triggering Article 110 boarding rights. AIS manipulation falls under ITU Radio Regulations, yet these instruments do not address enforcement mechanisms or the allocation of jurisdiction, leaving the gap unaddressed.

The IMO has focused on fraudulent registration, meaning fraud perpetrated during registration. While this focus can largely address various forms of fraud, identity fraud and registration fraud need to be distinguished, for they differ in their operation and intent. Registration fraud targets the administrative processes, corrupting the ship’s records. The intent may be to falsify ownership, obtain registration without full disclosure, or evade any liability. Once such registration has been obtained, the ship’s operation may be fully transparent.

Identity fraud targets the ship’s presentation to a third party, especially during the voyage. The IMO number and hull markings were added to prevent this misrepresentation, which rectified the problem for a limited time. Now, a ship’s name, hull markings, and other details are covered with a black cloth in certain areas affected by the US-Iran tensions in the Strait of Hormuz. It is a distinct category of physical masking to avoid third-party detection. 

Digital identity fraud, on the other hand, is neither registration fraud nor the masking of a ship’s physical identification layers. When the AIS-communicated apparent digital identity is faked, it might not indicate fraud in the registration per se, but rather manipulation of communication. Conflating AIS manipulation with nationality fraud misclassifies it as a form of manipulation that implies formal, documented manipulation.

Documentary identity manipulation operates at a different layer; it is not transient and can have an evidentiary basis that can be identified only by reviewing the ship’s records and matching them with the flag State’s registry records. Alternatively, the apparent digital identity manipulations are transient, occurring in real time, and accompanied by a difficult-to-establish evidentiary chain. These data must be captured and compared with the ship’s documentary records and, thereafter, with the registry records to identify discrepancies, miscommunications, or intent to commit fraud. 

On the high seas or beyond a physical verification limit, these distinctions are effectively blurred and likely obscure the differences among the various manipulations. These manipulations fall under different regulatory regimes (flag identity under UNCLOS; MMSI, as part of AIS manipulation, under ITU) and, therefore, treating them as equivalent without clear labels would leave States unclear about the applicable legal regime. 

These layered vulnerabilities allow illegal actors to exploit different components of a ship’s identity. The legal consequences vary depending on the component’s manipulation. Third-state challenges to nationality remain limited; AIS manipulation does not clearly indicate a ship’s statelessness if its documentary identity is intact. Without distinguishing these manipulations, enforcement authorities risk treating communication anomalies as registration fraud or nationality defects.

Conclusion

Ship identity is a dynamic concept with a distinct set of layers. Documentary and digital identity manipulation work at different target levels. The former manipulates recorded details while the latter miscommunicates transient information. Nationality, identified by the flag, is a related concept with distinct jurisdictional significance, yet not clearly distinguished in enforcement practice. Manipulation of identity is conflated with nationality manipulation and broadly categorised under false flag, creating an unwarranted tendency to infer statelessness, despite the high threshold under UNCLOS. Such conflations risk treating a digitally manipulated ship as stateless, thereby triggering Article 110 interdiction powers beyond the narrow circumstances contemplated by UNCLOS.