The procedural rules on dispute settlement are primarily contained in Part XV UNCLOS. These rules set out the conditions for UNCLOS tribunals to establish and exercise their compulsory jurisdiction hear contentious disputes. In addition to disputes between States, UNCLOS also grants the Seabed Disputes Chamber advisory jurisdiction pursuant to Article 191 UNCLOS. ITLOS as a full tribunal, however, has also found that it may exercise advisory jurisdiction despite the absence of an explicit provision to that effect under UNCLOS and the ITLOS Statute. This Chapter critically examines UNCLOS tribunals’ decisions relating the conditions for the establishment of compulsory jurisdiction in contentious proceedings under Part XV and the establishment of advisory jurisdiction of both the SDC and ITLOS as a full tribunal, in order to determine the extent to which UNCLOS tribunals have clarified the procedural law under the Convention.