This paper aims to determine whether there is uniformity in the interpretation of the UNCLOS Article 121.3 and whether the Arbitral Award can be considered as a threat to it. The historical context and the ambitions of the involved parties are presented and analyzed. In addition, an analysis of the treatment of the island regime   in international case law is carried out, as well as an analysis of the Tribunal’s interpretation of Article 121.3. The main finding is that there is no contestation regarding the uniformity its case law interpretation; but a necessary complement given the ambiguity of Article 121.3.