In January 2013 the Philippines invoked the dispute settlement system under UNCLOS in order to resolve its long-standing dispute with the People's Republic of China over the South China Sea and more specifically concerning Scarborough Shoal and the Spratly Islands. The arbitral tribunal constituted under Annex VII UNCLOS, without the PRC taking part in the proceedings as of yet, faces a challenging task in deciding whether or not it has jurisdiction over the case submitted by the Philippines. This article therefore examines the dispute settlement system of UNCLOS with regard to the jurisdiction of the tribunal in the pending Philippines-PRC South China Sea dispute. While at first glance UNCLOS appears to provide for a comprehensive system of compulsory jurisdiction, a number of exceptions, either applicable ipso facto or by virtue of unilateral declarations made at the time of signature or ratification of UNCLOS, leave only a thin layer of jurisdictional grounds, if any at all, for the arbitral tribunal to deal with and eventually decide the South China Sea dispute between the Philippines and the PRC. This implies that the arbitral tribunal is facing intriguing legal questions in this highly political procedure, the relevance of which extends far beyond the case at hand.