case-law, lady justice, justice


Krish Vikram, 1st Year Law Student, Symbiosis Law School Pune


The maritime boundary dispute between Mauritius and Maldives, centred around the Chagos Archipelago in the Indian Ocean, stems from colonial-era map discrepancies and subsequent territorial disagreements. Post-independence, Mauritius claimed the Archipelago, occupied by the UK. Maldives, geographically closest, wavered in its stance until President Solih supported Mauritius’ claim. The UN General Assembly’s Resolution led to the International Court of Justice (ICJ) issuing an advisory opinion in 2019, affirming Mauritius’ incomplete decolonization and the UK’s illegal occupation. Legal disputes escalated as Mauritius sought resolution under the UN Convention on the Law of the Sea (UNCLOS). Recent developments saw a Special Chamber hearing, where Maldives opposed Mauritius’ claim beyond 200 nautical miles. The Chamber ultimately favored Maldives in its judgment in April 2023, citing the Blenheim Reef’s role in delineation and dismissing Mauritius’ claims beyond 200 nautical miles due to uncertainties. The analysis explores the judgment’s strengths and shortcomings, emphasizing the necessity of proving entitlement, unresolved questions, and uncertainties regarding the continental shelf. This complex issue encompasses legal, technical, and geopolitical dimensions, implicating international interests in the region.

KEYWORDS – Delimitation Dispute, Chagos Archipelago, Continental Shelf, Geodetic Survey, Sovereignty, Exclusive Economic Zone.


This dispute on the delimitation of maritime boundaries between Mauritius and Maldives mainly revolves around the Chagos Archipelago in the Indian Ocean. Considering both these countries were colonised, the map that demarcated their territorial boundaries during colonisation and the modern-day map have huge differences, thereby resulting in territorial disputes. Post colonisation and independence of Mauritius in 1968, the Archipelago was claimed by Mauritius as its own territory but was still occupied by the United Kingdom. Meanwhile, even though the Archipelago is located closest to Maldives (500 Km south of Maldives) in term of geographical distance, Maldives has never taken a clear stand on the matter, having changed its position from time to time. However, recently Maldivian president Ibrahim Solih sent a letter to Mauritius President Pravind Jugnauth supporting Mauritius’ claim over the Chagos Archipelago. This decision of the president to send a letter turned out to be very controversial considering how a few view it as a masterstroke in furthering international relations whereas the critics believe the same to be a disregard to national interests. On 22 June 2017, when the matter was raised in the United Nations General Assembly, Resolution 71/292[1] was adopted to request the International Court of Justice (ICJ) to utilize its advisory opinion mainly on the Chagos Archipelago dispute. Finally, it was on 25th February 2019, the ICJ rendered its advisory opinion[2]

  1. The decolonisation of Mauritius was not carried out thoroughly and lawfully in 1968 when it gained its independence,
  2.  The occupation of Chagos Archipelago by the United Kingdom is an illegal occupation and the same must end as soon as possible,
  3. Cooperation from other United Nations member states to complete the decolonisation process of Mauritius.


In order to conduct a thorough analysis of the Delimitation of Maritime Boundaries, secondary sources were consulted for this descriptive article. For the research, secondary sources of information such as newspapers, journal articles, case laws and official websites are consulted.



The Maldives withdrew from any further talks even though they were aware that the waters overlapped, which has caused legal unrest in Mauritius. Mauritius so turned to Article 287 and Part XV of the Convention. It was made clear in Part XI that the parties to a disagreement should attempt to resolve it amicably by using a method of their choosing. In the meanwhile, parties are free to select the method of dispute resolution provided by Article 287. According to Article 287(2) and Annex VII of the Convention, the parties in question decided to have a special chamber settle their delimitation dispute. Furthermore, Mauritius asked the Special Chamber of ITLOS for a ruling in accordance with Article 34 of the Convention and Article 125 of the Rules.


Initially on 24th September 2019, A special agreement was signed between both the republics wherein they agreed to transfer the arbitration proceedings earlier instituted by Mauritius under Annex VII of the UNCLOS[3] to a Special Chamber of the International Tribunal for the Law of Seas. When the dispute was heard in a Special Chamber of the International Tribunal for the law of seas, both the nations Mauritius and Maldives gave their respective submissions as specified below –

Submissions of the Republic of Maldives

  1. Mauritius’ claim for a maritime boundary beyond its 200 nautical miles should be dismissed considering the claim is inadmissible and is outside the jurisdiction of the special chamber,
  2. The special chamber has no jurisdiction on the matter since an indispensable third party (United Kingdom) has been excluded (not a party) from the dispute. Hence, Mauritius’ claim is an abuse of process and needs to be dismissed,
  3. There is no dispute between the Mauritius and Maldives with regards to the maritime boundaries rather there exists an unresolved dispute between the United Kingdom and Mauritius with regards to sovereignty. Hence, the special chamber has no jurisdiction,
  4. Even though Article 74[4] and 83[5] of the UNCLOS calls for meaningful engagement and negotiation between the parties, the same cannot be done. Hence, the chamber lacks jurisdiction altogether,

Submissions of the Republic of Mauritius

  1. That the special chamber has jurisdiction to adjudicate and decide on the claim by Mauritius for a continental shelf beyond 200 nautical miles,
  2. The Chagos Archipelago dispute has been ongoing for at least since 2010 and the United Kingdom is not an indispensable third party,
  3. Maldives should pay a sum of 460,000 Euros to cover the cost incurred for the geodetic survey of the Blenheim reed and nearby waters and islands considering there was no cooperation from Maldives in conducting the geodetic survey (refusal to survey Maldivian territory),
  4. In light of the ICJ’s advisory opinion, there is no issue of sovereignty over the Chagos Archipelago with Maldives and hence, Maldives’ claim should be dismissed,
  5. The parties did engage in negotiation nevertheless, Article 74 and 83 of the UNCLOS imposes no obligation on negotiation and the same is not a precondition under Part XV[6] of the convention with regards to disputes of maritime boundaries,

Based on the preliminary and final submission by both nations that the special chamber gave its final judgment in favour of Maldives on 28th April 2023.


Maldivians claimed that Mauritius’ claim should be rejected because the “low tide elevation” surrounding the Blenheim Reef made it impossible for the area to be conquered. Nonetheless, the Tribunal determined that “low tide elevation,” whether partially or entirely, also constitutes a component of the coastline configuration within a State’s territorial sea by citing the case of Qatar v. Bahrain. In summary, the Tribunal determined that Blenheim Reef can be classified as a coastline line and, as such, be a part of a geographical formation.

Mauritius claimed to have the authority to decide the claim and to successfully demarcate the maritime region in accordance with the necessary parameters, and it submitted this declaration to the Special Chamber based on the facts and the law that were offered by both parties. Concerning the Maldives, they filed a request to the Special Chamber to declare Mauritius’ claim to the Chagos inadmissible, as they were one of the few nations to vote against the claim. The reason behind this is that the Maldives no longer acknowledge Mauritius’s ability to file a claim on behalf of the Chagos Islands. However, the Special Chamber’s ultimate ruling is still awaited.

It makes sense for the Maldives to adopt this stance and want the issue to be dropped or decided in their favor. It is possible that the Maldives will receive half of the rich fish waters if the EEZ is successfully delineated. Since its economy depends on exporting those fish to get money, this will eventually have an impact on it. On the other hand, Maldives is now more focused on its bilateral deal with Mauritius, its international relations, and the view of the world at large, all of which have the potential to negatively impact the country’s economy and tourism in the long run.

A quick review of the historic first maritime case involving Bangladesh and Myanmar is helpful. In 2011, Bangladesh, with comparable information, filed a lawsuit against Myanmar to demarcate their maritime borders in the Bay of Bengal, including their exclusive economic zone (EEZ) and continental shelf up to 200 nautical miles. Bangladesh was given a favourable ruling by ITLOS in this instance. The Tribunal in this specific case developed a three-step procedure that was subsequently applied in Ghana v. Cote D’Ivoire, which is significance. For the Tribunal to reach a just conclusion in this case, as it did in the previous two, Mauritius proposed applying the three-step process. Yet, it is crucial to remember that every case is unique and has its own set of circumstances.


Special Chamber on Preliminary objections – With regards to the first objection raised by Maldives on the United Kingdom being an indispensable third party, it was held that the United Kingdom is a state that doesn’t have sufficient legal interests let alone the term of an indispensable third party. Hence, with that this objection was dismissed.

With regards to the second objection of the dispute by Maldives on the sovereignty of the Archipelago, the special chamber held that Mauritius is a coastal state even before its decolonization for the purpose of delimitation of maritime boundaries. It was further affirmed that the same is concurrent with the Chagos arbitral ward and the Chagos advisory opinion based on UNGA resolution 73/295[7]. Hence, even this objection was dismissed.

With regards to the third objection on the requirement of fulfilment of Article 73 and 84 of the UNCLOS, it was held that according to Article 74 and Article 83 (Paragraph 1 of both) there was an obligation to negotiate but this obligation does not necessarily have to conclude with an agreement. Moreover, it was noted that Mauritius on several occasions reached out to Maldives for negotiating on the overlapping exclusive economic zones but unfortunately most of the time, there was a refusal from Maldives to cooperate. Hence, with that even the third objection by Maldives was rejected.

The Fourth objection raised by Maldives was that there was no dispute in the first place between Mauritius and Maldives hence, the chamber has no jurisdiction. The special chamber, here, noted that from the national legislations of both the countries, there is clearly an overlap of the exclusive economic zones.  Further it was held that a maritime boundary dispute does not have to necessarily deal with the location of the actual maritime boundary but can also be in other forms. Hence, in accordance to the above, this objection was rejected as well.

The final preliminary objection by Maldives was the abuse of process on the part of Mauritius to which the special chamber held that since Mauritius took up their dispute under Part XV of the convention (in concurrence with Article 74 and 83 of the convention), therefore, the claims raised by Mauritius are not an abuse of process. In conclusion, all of Maldives’ preliminary objection were dismissed.

Final Judgment – With regard to any dispute on the delimitation of maritime boundaries, the goal is to attain an equitable solution as stated in Article 74 and Article 83 (paragraph 1 respectively). The best method to attain an equitable solution is to use the equidistance circumstances method so as to effectively carry out the process of delimitation. The same has also been upheld in cases such as Bangladesh v. India[8] and Somalia v. Kenya[9]. Though international tribunals and courts, this equidistance method further developed into a three-stage approach (as used in the judgment) in determining maritime boundaries as specified in the case of Romania v. Ukraine[10].

Hence, keeping the above in mind, post hearing the final submission of both republics, the special chamber held that: –

  1. Applying the three-stage methodology for delimitation, it was held that –
  2. Blenheim Reef cannot be used as base point for maritime delimitation,
  3. The Blenheim Reef is a relevant circumstance and hence, justifies an adjustment to the equidistance line,
  4. There exists no gross disproportionality and hence, further adjustments to the boundary line need not be made.
  5. The chamber can carry out the delimitation of the continental shelf beyond 200 nm since the same is under its jurisdiction but they same would not be done in the present circumstances considering that even though there existed a fundamental disagreement between the parties, several scientific and technical issues were taken note of resulting

in significant uncertainties over Mauritius’ entitlement to the continental shelf beyond 200 nm. Therefore, the chamber concluded that it is not in a position to determine the matter.

Pictorial Analysis – Indicates an overlap in maritime boundaries; Blenheim reef is not the base point of the equidistance line; ITLOS ruled in favour of Maldives.


It is imperative to note that I concur with the judgment and the majority of the reasoning that upholds the judgment, nevertheless, valid criticisms have been elaborated below –

  1. Questions that remain clearly unanswered but yet relevant to the case include on whether filing a submission before the Commission on the Limits of the Continental Shelf (hereafter referred as CLCS) is mandatory procedurally for a court or tribunal to carry out delimitation of continental shelf beyond 200 nm. (considering Mauritius failed to present its submission before the CLCS within a reasonable period of time). Delving deep into the above, one can look at the case of Bangladesh/Myanmar[11] wherein it was held that the delimitation of the continental shelf beyond 200 nm (Under Article 83) and the delineation of outer limits (Under Article 76) are two different yet complementary aspects. Further there is no requirement for delineation to precede delimitation.
  • Question with regards to the entitlement of continental shelf beyond 200 nm; In most cases regarding delimitation of maritime boundaries, the parties must prove that they are entitled to the disputed boundary area and if they can’t prove the same delimitation would not be done since there exists no compelling object, yet there exists few exceptions depending on the facts and circumstances of the cases. Other aspects taken into consideration include submissions made before the CLCS (but the same does not per se mean entitlement to the disputed area). Something that should be kept in mind is that even when there is an absence of adversarial scrutiny of the parties, the claimant still has to show their entitlement to the disputed area keeping in mind the role of international parties and their interests.
  • The concept of Significant Uncertainties – In the case of Ghana/Côte d’Ivoire[12], Ghana had already received recommendations from CLCS whereas Côte d’Ivoire didn’t. Nevertheless, the special chamber recognised Côte d’Ivoire’s claim over the continental shelf beyond 200 nm considering its geographical status. But, in other cases where the claims were overlapping and submission got no recommendations from the CLCS, the test of significant uncertainties was applied as in the case of Bangladesh/Myanmar. This same test has also been applied in the present case since the issue concerns the international community in that area at large and their interests need to be protected as well. But criticisms include the fact that since there involved scientific and technical problems, an expert opinion should have been arranged for a better understanding on the scientific aspects of the matter. But unfortunately, the same was not done.


In conclusion, the maritime boundary dispute between Mauritius and Maldives over the Chagos Archipelago presents a complex and multifaceted issue with legal, technical, and geopolitical dimensions. The historical context rooted in colonial-era map discrepancies, combined with post-independence territorial claims, has fueled a prolonged and intricate legal battle. The United Nations General Assembly’s Resolution and the subsequent advisory opinion from the International Court of Justice in 2019 marked a significant milestone, affirming Mauritius’ incomplete decolonization and denouncing the UK’s illegal occupation of the Chagos Archipelago. However, the legal journey did not end there, as Mauritius pursued resolution under the United Nations Convention on the Law of the Sea (UNCLOS).

Recent developments, including the Special Chamber hearing, demonstrated the intricate nature of the dispute. Maldives, asserting its opposition to Mauritius’ claims beyond 200 nautical miles, secured a favorable judgment in April 2023. The decision hinged on the significance of the Blenheim Reef in delineation and dismissed Mauritius’ claims beyond the specified distance due to uncertainties. The analysis of the judgment reveals both strengths and shortcomings. The Tribunal’s recognition of the Blenheim Reef as a relevant circumstance in maritime delimitation adds nuance to the process. However, unresolved questions persist, particularly regarding the entitlement to the continental shelf beyond 200 nautical miles. The judgment’s emphasis on significant uncertainties underscores the importance of expert opinions in navigating complex scientific and technical issues.

Critically, the judgment’s dismissal of Maldives’ preliminary objections, including the alleged abuse of process by Mauritius, highlights the adherence to legal procedures in addressing the dispute. The consideration of jurisdictional issues, sovereignty claims, and negotiation attempts contributes to a comprehensive examination of the case. Nevertheless, valid criticisms emerge, raising questions about procedural requirements, the burden of proof for continental shelf entitlement, and the handling of significant uncertainties.

This maritime boundary dispute not only reflects the competing claims of two nations but also underscores the broader implications for international interests in the region. As the legal intricacies unfold, addressing the remaining questions and uncertainties becomes imperative for achieving a fair and equitable resolution that respects the rights and interests of all parties involved. In consideration of the above, it can be concluded that with regards to the claim of continental shelf beyond 200 nm this is a big victory for the Republic of Maldives. Regardless, according to the equi-distance principle, the dispute maritime area will be divided between Mauritius and Maldives. However, concerns regarding the implementation of the same are still prevalent. Finally, India having taken the side of Mauritius considering its strong foreign relations and similar past experiences of colonisation under the British. At the same time, relations with Maldives are also being focused upon keeping in mind Maldives’ President’s agenda of India first. Only time can tell the course of foreign relations between the neighbouring nations and whether an everlasting agreement on the dispute has been arrived upon or not.


  1. Primary Sources

 Conventions and Resolutions

  1. United Nations Convention on the Law of Seas, 1982 (UNCLOS).
  2. UNGA, A/RES/71/292, 71st session, Agenda Item 87, 22nd June 2017.
  3. ICJ, 25th February 2019, General List No. 169.
  4. UNGA, A/RES/73/295, 73rd session, Agenda item 88, 24th May 2019.

             Judicial Decisions

  1. Bay of Bengal Maritime Boundary Arbitration between Bangladesh and India, In re, 2014 SCC OnLine PCA 1.
  2. Somalia v. Kenya, 2014 SCC OnLine ICJ 13.
  3. Romania v. Ukraine, 2009 SCC OnLine ICJ 4
  4. Dispute Concerning Delimitation of the Maritime Boundary between Bangladesh and Myanmar in the Bay of Bengal, In re, 2012 SCC OnLine ITLOS 2.
  5. Delimitation of the Maritime Boundary in the Atlantic Ocean (Ghana/Côte d’Ivoire), Judgment, ITLOS Reports 2017, p. 4.
  6. Delimitation of the Maritime Boundary in the Indian Ocean (Mauritius/Maldives), Judgment, ITLOS, 28th April 2023, Case No. 28.
  • Secondary Sources

               Journal Articles

  1. Zhuang Yuan, On the Effectiveness of ICJ’s Advisory Opinions in the settlement of International Disputes: From the Perspective of the Mauritius/Maldives Case, China Oceans Law Review, Vol. 18 No.4, 155-160.
  2. Craig D. Gaver, Dispute Concerning Delimitation of the Maritime Boundary Between Mauritius and Maldives in the Indian Ocean, The American Journal of International Law, Vol. 115 No. 3, 519-526.
  3. Web Sources
  4. A.N. Honniball, Judgment in Dispute concerning delimitation of the Mauritius/Maldives Maritime Boundary, 28.04.2023, De Maribus.

Retrieved From –

  • Amy Sanders & Naomi Hart, Maritime Boundary Decision Between Mauritius and Maldives, 03.05.2023, Essex Court Chambers.

Retrieved From-

  • N. Sathiya Moorthy, Maldives: Border Settlement with Mauritius, 16.05.2023, Observer Research Foundation.

Retrieved From –

  • Malika Shahid, Maldives wins Maritime Boundary Dispute with Mauritius, 28.04.2023, The Edition.

Retrieved From –

  • Sarah Thin, The Curious Case of the ‘Legal Effect’ of ICJ Advisory Opinions in the Mauritius/Maldives Maritime Boundary Dispute, 05.02.2021, European Journal of International Law: Talk.

Retrieved From –


[1] UNGA, A/RES/71/292, 71st session, Agenda Item 87, 22nd June 2017.

[2] ICJ, 25th February 2019, General List No. 169.

[3] 1982, United Nations Convention on the Law of Seas.

[4] Delimitation of the exclusive economic zone between States with opposite or adjacent coasts.

[5] Delimitation of the continental shelf between States with opposite or adjacent coasts.

[6] Settlement of Disputes

[7] UNGA, A/RES/73/295, 73rd session, Agenda item 88, 24 May 2019.

[8] Bay of Bengal Maritime Boundary Arbitration between Bangladesh and India, In re, 2014 SCC OnLine PCA 1.

[9] Somalia v. Kenya, 2014 SCC OnLine ICJ 13.

[10] Romania v. Ukraine, 2009 SCC OnLine ICJ 4.

[11] Dispute Concerning Delimitation of the Maritime Boundary between Bangladesh and Myanmar in the Bay of Bengal, In re, 2012 SCC OnLine ITLOS 2.

[12] Delimitation of the Maritime Boundary in the Atlantic Ocean (Ghana/Côte d’Ivoire), Judgment, ITLOS Reports 2017, p. 4

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