Tensions between Mauritius and the Maldives around the Chagos Islands: “The Maldives claimed certain rights over the maritime areas off their territory”

Are we heading towards a new intervention by international legal bodies to once again discuss the case of the Chagos Islands?

That’s hard to say at this stage. All that can be observed is that the question of maritime delimitation between Mauritius and the Maldives has been definitively resolved by the International Tribunal for the Law of the Sea.

In 2023…

Yes, in 2023, the Court rendered a judgment which indicates very clearly what are the delimitation lines between the two States in this part of the Indian Ocean and which recognizes the sovereignty of Mauritius over the maritime areas adjacent to the Chagos Islands.

During a press conference on Monday, Maldives President Mohamed Muizzu spoke of the important historical links between the Maldives and the Chagos Archipelago, referring to a letter dating from the 16th century, accompanied by a map of Chagos. The latter was written by King Hassan IX. In fact, the Maldives claim sovereignty over the Chagos Islands?

This is really something new for me, because having worked on the Chagos issue for quite a long time, first in the context of the advisory procedures before the International Court of Justice, then in that of the judicial proceedings for the delimitation of maritime areas before the International Tribunal for the Law of the Sea, there are very few, if not any, documents which state of sovereignty titles of the Maldives over Chagos.

On the contrary, during the colonial period, Chagos first came under French sovereignty. And from the moment France ceded Mauritius to the United Kingdom, it was the latter, as a colonial power, which exercised control over the Chagos. For centuries there was no trace of Maldivian presence, activity or sovereignty on the islands. So it’s a claim that seems quite surprising at this stage.

If the Maldives put together a case, can they rely on this letter from the 16th century?

It seems difficult, because in international law, there is no recognition of historical title as such. What matters are the events that have happened since then.

If you take similar situations, you could say: yes, in the 16th century, Belgium came under the sovereignty of Spain, then the Holy Roman Empire. We can find historical documents which show that sovereignty belonged to this or that power at a given time. But history evolves, and sovereignties change over the territories. So what is important is to take this development into account.

Mauritius has claimed sovereignty over the archipelago since the 1960s, and the United Kingdom officially retroceded the Chagos Islands to Mauritius in 2025. But before this retrocession, did the Maldives already claim certain areas, when the archipelago was under British control?

Not to my knowledge. According to the file presented at that time, the Maldives claimed certain rights over the maritime areas off its territory, up to the limit of 200 nautical miles provided for by the United Nations Convention on the Law of the Sea for the exclusive economic zone, and sometimes beyond for the continental shelf, but without ever claiming sovereignty over the the islands themselves. So this is a claim that seems completely new to me.

The treaty signed between the United Kingdom and Mauritius has aroused discontent, not only on the Maldives side, but also among the inhabitants of the archipelago, in particular of Diego Garcia Island, where the American military base is located. The latter had been expelled and deported to Mauritius and the Seychelles, and wish to return to Diego Garcia Island. Is it possible to return to this treaty, considered by some to be not very inclusive?

The agreement between Mauritius and the United Kingdom of 2025 aims at the retrocession of territories and recognition of the sovereignty of Mauritius over the islands.

Issues related to the management of the islands, such as access, are the responsibility of the Mauritian authorities and the facilities they can put in place. The resettlement of populations on Diego Garcia would be extremely complicated, because Mauritius has agreed to continue to make the island available to the United States and the United Kingdom for the military base.

Resettlement rather concerns other parts of Chagos. As you said, it is a very large archipelago, with scattered islands and limited surface area for most. There are significant practical problems, as these islands have been abandoned for over 50 years and no infrastructure exists, with the exception of Diego Garcia.

So the question of resettlement is crucial. This was a major demand of the Chagossians expelled in the 1970s. It is a concern which continues to be taken into account by the Mauritian authorities.