{"id":1720,"date":"2026-08-25T15:13:03","date_gmt":"2026-08-25T13:13:03","guid":{"rendered":"https:\/\/site.uit.no\/nclos\/?p=1720"},"modified":"2026-08-25T15:13:03","modified_gmt":"2026-08-25T13:13:03","slug":"unclos-articles-137-and-139-what-they-do-and-what-they-do-not-regulate","status":"publish","type":"post","link":"https:\/\/site.uit.no\/nclos\/2026\/08\/25\/unclos-articles-137-and-139-what-they-do-and-what-they-do-not-regulate\/","title":{"rendered":"UNCLOS Articles 137 and 139: What They Do\u2014and What They Do Not\u2014Regulate"},"content":{"rendered":"\n

By Nathan Eastwood, Haeran Chung and Iuliia Samsonova<\/em><\/p>\n\n\n\n

1. Introduction<\/strong><\/p>\n\n\n\n

    <\/ol>\n\n\n\n

    Do Articles 137 and 139 of the United Nations Convention on the Law of the Sea<\/a> (UNCLOS<\/strong>) establish a universal legal regime governing all seabed mineral activities, irrespective of the regulatory framework under which they occur? This question has gained renewed prominence as prolonged delays by the International Seabed Authority<\/a> (ISA<\/strong>) in finalizing Exploitation Regulations have accelerated corporate interest in seabed mineral activities outside the UNCLOS regime, particularly under the United States\u2019 Deep Seabed Hard Mineral Resources Act<\/a> (DSHMRA<\/strong>).<\/p>\n\n\n\n

    This post examines the scope of UNCLOS Articles 137 and 139 in relation to deep seabed mining activities conducted outside the UNCLOS regime. In our interpretation, neither provision imposes a blanket prohibition on such activities. Rather, both operate within the institutional framework of Part XI of UNCLOS.<\/p>\n\n\n\n

    2. The scope of Article 137 <\/strong><\/p>\n\n\n\n

      <\/ol>\n\n\n\n

      Article 137 sets out that no State may claim sovereignty or sovereign rights over the Area or its resources, that rights in resources are vested in humankind as a whole, and that minerals recovered from the Area may be alienated only in accordance with Part XI and ISA rules. Article 137(3) then provides that \u201cNo State or natural or juridical person shall claim, acquire or exercise rights with respect to the minerals recovered from the Area<\/strong> except in accordance with this Part. Otherwise, no such claim, acquisition or exercise of such rights shall be recognized<\/strong><\/em>.<\/strong>\u201d (Emphasis added).<\/p>\n\n\n\n

      To understand precisely what Article 137(3) does and does not do, it is critical to examine carefully the text of this provision. UNCLOS provisions, including Article 137(3), must be interpreted in accordance with Article 31 of the <\/a>Vienna Convention on the Law of Treaties<\/a> (Vienna Convention<\/strong>), i.e. in good faith, in accordance with their ordinary meaning, in their context, and in light of the object and purpose of UNCLOS.<\/p>\n\n\n\n

      Applying the Vienna Convention<\/a> rules on treaty interpretation, it is clear that Article 137(3) is intended to serve as a safeguard for UNCLOS\u2019 principle concerning the common heritage of humankind by prohibiting, among other things, the claim, acquisition or exercise of rights \u201cwith respect to<\/em>\u201d minerals recovered from the Area outside of the UNCLOS regime by UNCLOS States Parties, and the non-recognition of rights in respect of such minerals, thereby diminishing the economic incentive for any such recovery. Whether Article 137(3), or aspects of it, also reflects customary international law so as to bind non-Parties is a distinct question, which is considered separately below.<\/p>\n\n\n\n

      Two aspects of Article 137(3) are significant.<\/p>\n\n\n\n

      First, Article 137(3) is concerned with rights in the minerals themselves\u2014that is, claiming, acquiring or exercising rights in<\/em> (\u201cwith respect to<\/em>\u201d) the physical seabed minerals recovered from the Area. It does not purport to regulate the full range of commercial activities that may be directly or indirectly associated with an entity involved in the physical recovery of seabed minerals.<\/p>\n\n\n\n

      While some commentators advocate a broader understanding of the provision\u2019s practical effects (see, e.g., Toby Fisher and Samantha Robb<\/a>), the text does not address investments, financing, goods and services contracts, corporate restructurings, or offtake arrangements as such. Properly construed, Article 137(3) regulates the legal status of rights in recovered minerals, not participation in the wider commercial ecosystem surrounding seabed mining projects.<\/p>\n\n\n\n

      Second, the legal consequence specified by Article 137(3) is non\u2011recognition of those rights in the minerals. According to the International Court of Justice (ICJ<\/strong>), the obligation of non-recognition includes refraining<\/strong> from any acts or dealings which may \u201c[imply] recognition of the legality of, or [lend] support or assistance to\u201d<\/em> an unlawful act or situation (see e.g., Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa) notwithstanding Security Council Resolution 276 (1970)<\/em>, Advisory Opinion of 21 June 1971<\/a>, paras. 119, 133.). Therefore, Article 137(3) cannot be interpreted as imposing on non\u2011sponsoring States Parties a duty to take active enforcement or regulatory measures against companies, subsidiaries or nationals within their jurisdiction merely because they are connected with activities conducted pursuant to a non\u2011Party\u2019s domestic seabed mining regime.<\/p>\n\n\n\n

      The obligation of non-recognition arises only where there is an illegal or unlawful act or situation under international law<\/strong>. A US national licensed to explore or commercially recover seabed minerals under DSHMRA cannot be considered illegal or unlawful as a matter of international law.<\/p>\n\n\n\n

      Article 137(3) is neither framed as, nor capable of supporting, an obligation to criminalize conduct, deny port access, restrict financial services, or regulate downstream commercial activity. Such measures remain matters of domestic policy rather than obligations imposed by UNCLOS.<\/p>\n\n\n\n

      3<\/strong>. Article 137 as a regime\u2011conditional recognition rule<\/strong><\/p>\n\n\n\n

      Read in the context of Part XI, Article 137(3) operates as a regime\u2011conditional recognition clause. Since the ISA acts \u201con behalf of [hu]mankind<\/em>,\u201d and Article 137(2) permits the alienation of minerals recovered from the Area only in accordance with Part XI and ISA rules, States Parties agree, as between themselves and within the UNCLOS framework, not to recognize claims to such minerals unless they arise pursuant to that regime.<\/p>\n\n\n\n

      What Article 137 does not do is establish a self\u2011executing rule of global private law that nullifies title under all domestic legal systems. Questions concerning whether proprietary interests arise in recovered minerals are ordinarily resolved through domestic law and private international law<\/strong>, including conflict\u2011of\u2011laws rules governing title to movables. UNCLOS does not purport to (nor could it) displace those rules in relation to non\u2011Parties.<\/p>\n\n\n\n

      4.<\/strong> Treaty obligations and third States<\/strong><\/p>\n\n\n\n

      Article 137 is, in form and substance, a treaty obligation<\/strong>. Under well\u2011established principles of the law of treaties, \u201c[a] treaty does not create either obligations or rights for a third State without its consent<\/em>.\u201d<\/p>\n\n\n\n

      It follows that Article 137 cannot, as a matter of treaty law alone, prohibit conduct carried out under the authority of a non\u2011Party, nor can it impose direct legal obligations on private actors by virtue of UNCLOS itself. Any claim that Article 137 binds non\u2011Parties therefore depends on an additional proposition: that the relevant rules have crystallized as customary international law<\/strong>.<\/p>\n\n\n\n

      5.<\/strong> Customary international law considerations<\/strong><\/p>\n\n\n\n

      Although binding as treaty law on States Parties, Article 137 of UNCLOS has not attained the status of customary international law because it does not satisfy the cumulative requirements of general and consistent State practice and opinio juris<\/em>. At the time of its adoption, Article 137 did not reflect pre\u2011existing custom, but rather constituted a negotiated legal innovation embedded within a comprehensive treaty framework governing the \u201ccommon heritage of [hu]mankind<\/em>.\u201d<\/p>\n\n\n\n

      Subsequent practice likewise does not demonstrate the crystallization of a customary rule. State compliance with Article 137 is readily explained by treaty obligation, and practice relating to the Area remains closely tied to participation in UNCLOS institutions, particularly the ISA, and to rights exercised pursuant to ISA contracts. There is little evidence that States regard Article 137 as binding independently of treaty consent.<\/p>\n\n\n\n

      Nor is there sufficient evidence of opinio juris<\/em>. While a number of States have asserted that unilateral activity in the Area would be unlawful and that the common heritage of humankind forms part of customary international law, those statements emanate largely from States Parties to UNCLOS (see James Kraska<\/a>). There is comparatively little evidence that non-Parties to UNCLOS accept Part XI, or the non-appropriation regime it establishes, as reflecting customary international law. This limits the weight that can be accorded to the available statements as evidence of a general and representative opinio juris<\/em> capable of supporting the crystallization of a customary rule.<\/p>\n\n\n\n

      Even if it were argued that Article 137, or elements of Part XI, had gradually evolved into customary international law since their adoption, such a rule would not bind States that have persistently objected to it (see e.g., James Kraska<\/a> and Michael Lodge<\/a>). Critically, the United States has persistently objected to Article 137 of UNCLOS imposing any restrictions or obligations on non-State Parties. The United States has consistently maintained that it has the right to engage in activities in the Area under the customary international law principle of the freedom of high seas. That position has been accompanied by sustained contrary practice, including the maintenance and updating of a domestic regulatory framework under DSHMRA, administered by NOAA<\/a>, authorizing US nationals to engage in deep seabed activities.<\/p>\n\n\n\n

      6. The problem of Article 139<\/strong><\/p>\n\n\n\n

      Attention often turns, at this point, to Article 139 of UNCLOS, which requires States Parties to \u201censure<\/em>\u201d that activities in the Area carried out by their nationals or entities under their effective control comply with Part XI. That provision is sometimes treated as supplying the universal reach that Article 137 is said to lack.<\/p>\n\n\n\n

      Article 139 binds States, and States only. As the Seabed Disputes Chamber explained in the Area Advisory Opinion<\/em><\/a>, sponsorship serves as the mechanism through which States Parties ensure compliance by private entities operating within the UNCLOS framework.<\/p>\n\n\n\n

      While the necessity of sponsorship is stipulated in Article 153(2), the core duties of sponsoring States are defined in Article 139. It is in that context that Article 139 imposes an obligation on States to \u201censure<\/em>\u201d that \u201cactivities in the Area<\/em>\u201d are carried out in accordance with UNCLOS, irrespective of whether the actor is the State itself, one of its enterprises, or a private entity sponsored by it. This note does not analyze the nature of the \u201censure<\/em>\u201d obligation enshrined in Article 139, a matter which has been extensively dealt with in the Area Advisory Opinion<\/em><\/a>, <\/em>albeit solely in the context of sponsoring States operating within the Part XI framework. The focus is instead on ascertaining which State Parties, and in respect of which private parties, Article 139 purports to address.<\/p>\n\n\n\n

      Those who advocate a central role for Article 139 in preventing deep seabed mining outside the ISA regime argue that the provision is best construed as imposing on all<\/em> States a duty to regulate the conduct of all <\/em>of their nationals with respect to deep sea mining, and not merely a duty binding States that are themselves conducting, or sponsoring, activities in the Area (see, e.g., Coalter Lathrop\u2019s NCLOS blog post<\/a>). On this view, Article 139 requires States Parties to exercise their jurisdiction so as to give effect to the supposed exclusivity of the ISA framework. The argument therefore continues that States Parties are obliged to deploy their domestic law, and ultimately their State apparatus, to restrain their own nationals from becoming involved in exploration or exploitation activities even where those nationals have no sponsorship arrangement with the State Party in question. On a practical level, that interpretation would require States to prevent their nationals from accepting employment or consultancy engagements, or appointments to advisory or managerial roles, in connection with such projects. For convenience, this may be described as the States Parties\u2019 alleged duty to restrain nationals.<\/p>\n\n\n\n

      The argument turns on Article 139 reference to nationals and entities under the effective control of States Parties. The key questions are whether the provision applies to all nationals of States Parties (the Nationals Issue<\/strong>) and whether \u201cactivities in the Area\u201d extends to any form of participation in an exploration or exploitation project (the Participation Issue<\/strong>).<\/p>\n\n\n\n

      The \u2018Nationals Issue\u2019<\/em><\/strong><\/p>\n\n\n\n

      Interpreted consistently with the Vienna Convention<\/a>, Article 139 is arguably best understood as operating within the sponsorship framework established by Part XI. Its language closely tracks Article 153(2), which provides that activities in the Area are carried out by States Parties, state enterprises and private entities acting under State sponsorship. Article 139 therefore defines the obligations of States Parties in relation to those actors. On this reading, the provision does not apply to all nationals of States Parties as such, but only to those nationals and entities participating within the sponsorship framework established by Part XI and Annex III.<\/p>\n\n\n\n

      Indeed, the ISA itself adopted that position in its written statement<\/a> to the Seabed Disputes Chamber in the advisory proceedings. It argued:<\/p>\n\n\n\n

      \u201c[Obligation of States to assist the Authority under] Article 153, paragraph 4, [\u2026] is met through compliance with the due diligence obligation set out in article 139 of the Convention, to ensure that the activities in the Area conducted by the sponsored contractor are in conformity or in compliance with those rules<\/strong><\/em>\u201d (Emphasis added).<\/a><\/p>\n\n\n\n

      As that passage makes clear, the subject matter of the obligation is regulatory oversight over the sponsored contractor<\/em>, not over other nationals as such. To the same effect, a leading Commentary on Article 139 concludes that \u201cthe primary obligation provided for in Art. 139 (1) \u2026 must be read as referring to sponsoring States.<\/em>\u201d (A H\u00f6felmejer \u2013 S V\u00f6neky, \u2018Article  <\/em>139\u2019, in A Proells (ed), United Nations Convention on the Law of the Sea<\/em><\/a> (Beck 2017), p.972)<\/p>\n\n\n\n

      Further, Article 139, again mirroring Article 153, imposes a duty with respect not only to nationals, but also to juridical persons that are under the effective control of a State Party or its nationals. As Ambassador Georgina Guill\u00e9n-Grillo and Salvador Vega note in their ISA briefing paper, \u201cnationality and effective control are separate criterion <\/em>[sic]\u201d<\/a> (Briefing Paper on Conceptual Topics Related to the Informal Working Group on Institutional Matters: Effective Control<\/a>, facilitated by Ambassador Georgina Guill\u00e9n-Grillo and Salvador Vega, March 2024). We note for clarity that the authors\u2019 reference to this piece should not be construed as indication of their agreement with its contents in its entirety.<\/p>\n\n\n\n

      Therefore, UNCLOS contemplates obligations in respect of entities that may not possess the nationality of the sponsoring State. Yet international law does not, as a general rule, recognize an unlimited right of a State to regulate foreign juridical persons merely because they are controlled by its nationals. Corporate nationality is distinct from the nationality of shareholders or controllers. In the classic formulation of the ICJ, corporate nationality is ordinarily linked to incorporation and registered office, and not simply to the nationality of those holding an economic interest in the company<\/a> (Barcelona Traction, Light and Power Company, Limited (Belgium v Spain)<\/em> (Second Phase) [1970] ICJ Rep 3<\/a>, paras 70-71. See <\/em>also Article 9 of the ILC Articles on Diplomatic Protection<\/a>). Ordinarily, a mere link of control between nationals and a foreign entity does not confer the right on the State of nationality to regulate the conduct of the foreign entity. It may regulate the conduct of its own <\/em>nationals, including with respect to how they exercise their right to, or de facto <\/em>ability to, control foreign entities: but this is not jurisdiction <\/em>over the controlled entity as such.<\/p>\n\n\n\n

      Article 31(3)(c) of the Vienna Convention<\/a> directs attention to other relevant rules of international law applicable in the relations between the parties. In determining over which actors States are expected, under Article 139, to exercise jurisdiction with a view to ensuring compliance with UNCLOS, rules governing corporate nationality are relevant limiting factors. Against that backdrop, the only workable construction of Article 139 is that it is by virtue of the sponsorship<\/em> arrangement with the private entity that the State Party becomes both entitled, and required, to exercise due diligence and regulatory oversight over that entity\u2019s conduct in circumstances where the entity is not its national. Sponsorship thus operates as a sui generis<\/em> connecting factor: it enables, and at the same time requires, a form of regulatory supervision that would otherwise be difficult to justify under the ordinary bases of jurisdiction recognized by international law. The relevance of this analysis for the purposes of interpreting Article 139 is that, given its reference to \u201ceffective control<\/em>\u201d, it could not have been intended as a provision to regulate supervision over any and all nationals of State Parties, nor over any and all effectively controlled parties.  We note, however, that recent commentary has advanced differing views as to the scope of Article 139 (see, e.g., Coalter Lathrop<\/a> and Ekaterina Antsygina<\/a>).<\/p>\n\n\n\n

      Subsequent practice also supports a narrow interpretation of Article 139. Subsequent practice in the application of a treaty is the \u201cmost important element in the interpretation of any treaty, and reference to practice is well established in the jurisprudence of international tribunals<\/em>\u201d (A Aust, Modern Treaty Law and Practice<\/em><\/a> (CUP 2013), p. 215). Here, that practice includes the way in which the ISA has implemented Article 139 in its exploration regulations<\/a>. Specifically, the ISA requires the certificate of sponsorship to include a declaration that the sponsoring States assume \u201cresponsibility in accordance with articles 139 and 153 (4) of the Convention and article 4 (4) of annex III to the Convention<\/em>\u201d. <\/a> This demonstrates that the ISA has operationalized Article 139 through the sponsorship relationship contemplated by the Convention and has not sought to establish mechanisms through which non-sponsoring States would supervise or incur responsibility for the activities of contractors sponsored by other States. That practice supports the view that Article 139 is principally concerned with responsibility arising from sponsorship, rather than imposing a general obligation on all States Parties to regulate every national engaged in activities in the Area.<\/p>\n\n\n\n

      The \u2018Participation Issue\u2019<\/em><\/strong><\/p>\n\n\n\n

      Turning to the Participation Issue, we suggest that an expansive reading of Article 139 is equally difficult to sustain. If the phrase \u201ccarrying out activities in the Area<\/em>\u201d were interpreted to encompass any degree of participation in an exploration or exploitation project, Article 139 would require multiple States Parties to exercise concurrent oversight whenever their nationals were employed by, advised, or otherwise assisted a sponsored contractor. Such a construction would fragment, rather than clarify, responsibility under Part XI. Read in context, \u201ccarrying out activities in the Area<\/em>\u201d is better understood as referring to the conduct of the sponsored contractor, or other entities directly authorized within the Part XI framework, rather than persons contributing in an ancillary or professional capacity.<\/p>\n\n\n\n

      7. Implications of Article 139 for the US regulatory framework<\/strong><\/p>\n\n\n\n

      A final point should be made regarding the implications of Article 139 for participation in projects licensed under a US domestic regime. Article 139 speaks of an obligation to \u201censure<\/em>\u201d compliance with UNCLOS. Since UNCLOS binds its States Parties, the obligation to ensure compliance arises only where compliance with UNCLOS is legally in issue. The US is not a party to UNCLOS. Its conduct, as such, cannot be characterized as non-compliant with UNCLOS, because UNCLOS does not apply to it as a treaty matter. Accordingly, even if Article 139 were given the wider interpretation discussed above, and extended to all nationals and all forms of participation, involvement in exploration or exploitation programmes licensed by a non-party would not present a question of compliance with UNCLOS. Moreover, the language of Article 139 is directed to conformity with Part XI of UNCLOS; it does not, a contrario<\/em>, require States Parties to ensure compliance with customary international law or with law of the sea instruments external to UNCLOS.<\/p>\n\n\n\n

      <\/p>\n