On 19 May 2025, the International Court of Justice (the “ICJ” or “Court”) issued its judgment in Land and Maritime Delimitation and Sovereignty over Islands, between the Gabonese Republic (“Gabon”) and the Republic of Equatorial Guinea (“Equatorial Guinea”).
In November 2016, Gabon and Equatorial Guinea (the “Parties”) entered into a Special Agreement that submitted to the ICJ their dispute on “delimitation of their common maritime and land boundaries”, as well as “sovereignty over” Mbanié/Mbañe, Cocotiers/Cocoteros and Conga, which are off the west coast of Africa (the “Islands”). The Court had to determine “whether the legal titles, treaties and international conventions invoked” by the Parties had the force of law between them. Given the Parties’ opposing arguments, the ICJ had to determine what constituted a “legal title” within the Special Agreement. The Court stated that, when a treaty contains a “term of art”, there is a presumption that the Parties intended to give the term the meaning it “generally bears” under international law. Recalling its previous jurisprudence, the Court found that “legal title” comprehends “both any evidence which may establish the existence of a right, and the actual source of that right”. Accordingly, the term “legal title” within the Special Agreement “refers to title also as the source of a right”.
The Court then examined whether the convention delimiting the land and maritime frontiers of Equatorial Guinea and Gabon (the “Bata Convention”) was a “legal title” under the Special Agreement. The Court recalled that, under the applicable law (customary international law), the “intention of the parties to be legally bound is necessary for an instrument to constitute a treaty”. By 14 votes to one, the ICJ found that the Bata Convention “is not a treaty having the force of law”, and thus “does not constitute a legal title”. In drawing this conclusion, the Court considered the terms of the Bata Convention, the circumstances in which it was drawn up, and the subsequent conduct of the Parties.
The ICJ next examined the legal titles, treaties and international conventions invoked by the Parties concerning (i) delimitation of a common land boundary, (ii) sovereignty over the Islands, and (iii) delimitation of a maritime boundary.
As for (i), the ICJ unanimously held that the territorial titles held by the Parties at their independence had the force of law between them “as far as they concern the delimitation of their common land boundary”. In its reasoning, the Court noted the Parties’ agreement that, upon their independence in 1960 (Gabon) and 1968 (Equatorial Guinea), the Parties became successors to the titles to territories held by France and Spain, respectively. The basis for those titles was the Special Convention on the delimitation of French and Spanish possessions in West Africa, on the coasts of the Sahara and the Gulf of Guinea (the “1900 Convention”). The Parties disagreed on whether the boundary described in Article IV of the 1900 Convention had been modified in accordance with the terms of the 1900 Convention. After a detailed analysis of the factual record, the Court concluded that “no modifications were made to the boundary described in Article IV”.
As for (ii), the Court held (by 13 votes to 2) that the title to the Islands was that held by Spain and succeeded to Equatorial Guinea on its independence, while the 1900 Convention was not a source of “legal title”. The ICJ also assessed whether there had been a display of authority over the Islands through the exercise of State functions. Based on documentary evidence and practice, the Court concluded that, when Equatorial Guinea had achieved its independence in 1968, Spain, as the colonial Power, held title to the Islands due to its continuous and uncontested “intentional display of authority”. In reaching its decision, the Court noted that, (a) after Gabon’s independence from France, Gabon recognised Spain’s title over the Islands; and (b) after Equatorial Guinea’s independence from Spain, Equatorial Guinea maintained control over the Islands.
As for (iii), the Court unanimously found that the 1900 Convention constituted “legal title”. Because Article IV of the 1900 Convention established the “terminus of the land boundary” between the Parties, it was the “starting-point of the maritime boundary delimiting their respective maritime areas”. The ICJ also unanimously held that UNCLOS has the force of law between the Parties “in so far as it concerns the delimitation of their maritime boundary”. The Court here stated that, although “UNCLOS may ‘concern’ the delimitation of the Parties’ common maritime boundary, it is not itself the source of a right to specific maritime areas”. The ICJ further stated that “the principle that the land dominates the sea does not automatically assign coastal States rights to specific maritime areas”, reasoning that, “[w]hile the principle may ‘concern’ the delimitation of the Parties’ common maritime boundary, it is not itself the source of a right to specific maritime areas”.
The ICJ’s full judgment is here.
The separate opinions of Judges Yusuf and Tladi are here and here.
The declarations of Judges Xue and Aurescu and Judge ad hoc Wolfrum are here, here and here.
The dissenting opinion of Judge ad hoc Pinto is here.