2.5 IMO’s role as a competent organization under UNCLOS
As noted earlier in this thesis, the oceans are essential to facilitating global trade, which underpins effective supply chains and plays a central role in maritime security. Given the transboundary nature of maritime activities, the regulatory governance of the oceans is necessarily international in character(1)Min Zhu and Linchi Qu, ‘Text classification of issues concerning implementation of IMO instruments based on deep bidirectional language representation model’ (11.12.2025) Discover Artificial Intelligence, Volume 6 article number 28 (2026), chapter 1. UNCLOS assigns a central role to the IMO, which functions as an important forum for the development of global rules and standards applicable to shipping(2) Article 211(1) UNCLOS.
UNCLOS has been described as a framework convention, and it has been pointed out that it does not constitute a separate or self-contained legal regime(3)Alan Boyle, ‘Further Development of the Law of the Sea Convention: Mechanisms for Change’ (July 2005), The International and Comparative Law Quarterly, Oxford, Vol. 54 issue 4, page 565. Rather, UNCLOS is a treaty that operates within a larger legal system, and scholars have argued that “The Convention was intended to have the flexibility to respond to change”(4)Ibid n114, page 584. Change can take many forms, such as, for example, negotiated multilateral agreements like the BBNJ Agreement. While not departing from UNCLOS, it can be seen as an evolution and concretisation of the overarching obligations from UNCLOS. In addition to referencing general rules of general international law, UNCLOS also incorporates “generally accepted international rules and standards established through the competent international organization”(5)Article 211(2) UNCLOS. The IMO is recognised in UNCLOS as “the competent international organization”(6)Articles 211, 217, and 233 UNCLOS, establishing a structural link between UNCLOS and the IMO’s regulatory output. The reliance on generally accepted international rules and standards is not confined to regulation solely concerning shipping activities, but it is a representation of the broader legislative methodology employed across UNCLOS to constitutionalize duties while delegating their more technical elaboration to specialised international regimes(7)Robert Beckman, ‘IMO Seminar on Development of a Regulatory Framework for Maritime Autonomous Surface Ships (MASS)’(September 2022) Centre for International Law National University of Singapore,https://wwwcdn.imo.org/localresources/en/OurWork/Safety/PublishingImages/Pages/MASS/04_Robert%20Beckman_The%20implication%20of%20MASS%20on%20the%201982%20United%20Nations%20Convention%20on%20the%20Law%20of%20the%20Sea.pdf accessed the 11.05.2026, pages 3 and 10. At the same time, UNCLOS places significant responsibility on the States, requiring them to give effect to internationally agreed rules, standards, and recommended practices and procedures(8)Article 207(1) UNCLOS through the adoption of appropriate national laws and regulations.
Within the IMO framework, generally accepted international rules and standards relating to maritime safety, navigation, security, and the protection of the marine environment are articulated through a combination of binding conventions and non‑binding instruments(9)Articles 94 and 211(2) UNCLOS. These standards acquire legal significance under UNCLOS through their implementation at the national level, as States are required to give effect to them in the exercise of their jurisdiction and control over ships flying their flag, primarily through flag State jurisdiction(10)Articles 94(1)–(4) and 211(2) UNCLOS.
A key aspect of the IMO’s role as the competent international organization under UNCLOS concerns how the standards it develops come to be regarded as “generally accepted international rules and standards”(11)Article 211(2)(5)(6c) UNCLOS for the purposes of flag State obligations. While UNCLOS itself does not define what level of acceptance is required to achieve general acceptance, the issue has received judicial attention, notably in the South China Sea Arbitration(12)Ibid n111, paragraphs 1038-1040. In that case, the Tribunal was required to interpret Article 94 in the context of flag State duties and examined whether the International Regulations for Preventing Collisions at Sea (‘COLREGs’), as an instrument adopted under the IMO, satisfied UNCLOS’ requirement of general acceptance. While an analysis of the threshold for general acceptance is not a focus of this thesis, the Tribunal’s reasoning is deemed relevant for understanding how flag State obligations under UNCLOS can be attributed concrete content through international shipping standards. In the South China Sea Arbitration, the Tribunal placed emphasis not on COLREGs’ formal status alone, but on their widespread adoption and consistent application in practice(13)Ibid n111, paragraph 1081. The COLREGs apply to all vessels on the high seas, meaning a large majority of the world’s merchant fleet(14)IMO, ‘Convention on the International Regulations for Preventing Collisions at Sea1972’ https://www.imo.org/en/about/conventions/pages/colreg.aspx accessed the 20.04.2026, Rule 1. The Tribunal concluded that the COLREGs qualified as generally accepted rules and were incorporated into UNCLOS through Article 94 and were therefore legally binding on the parties(15)Ibid n111, paragraph 1083. This reasoning suggests that general acceptance under UNCLOS does not depend on formal adoption alone, but also on recognition and consistent implementation.
The Tribunal’s approach provides guidance on how and when IMO-developed standards could acquire normative force for the purposes of flag State obligations under UNCLOS. The BBNJ Agreement relies on flag State jurisdiction and control, and the intention is that the BBNJ Agreement shall operate in coordination with existing sectoral regimes. Because the BBNJ Agreement itself does not set detailed rules for ship operation on the high seas, flag States are likely to rely on IMO-developed standards. This interaction may also be shaped indirectly by the objectives of the BBNJ Agreement, as States that are simultaneously parties to the BBNJ Agreement and members of the IMO are under an obligation to promote the BBNJ objectives when participating in decision‑making within other relevant sectoral bodies(16)Article 8(2) BBNJ Agreement. The relevance of IMO standards may in turn depend on similar indicators of general acceptance as identified by the Tribunal in the South China Sea Arbitration.