The UNCLOS has been since its signature in 1982 the fundamental international legal reference for oceans governance. Indeed, this treaty was written “in pursuit of our common dream of writing a constitution for the oceans”. Yet much alike any dream, reality sooner or later catches up. The reality here is that of unilateral state practice and that practice has been relying, at least to some extent, on general public international law. This chapter explains how it is important to revisit international law to better understand the relative relevance of the UNCLOS in oceans governance today. Indeed, treaty law is only one of many sources of the law that governs international relations, the others being customary international law and principles of law. The main conclusion of this chapter is that states may have to wake up to the limitations of the UNCLOS and that this will require understanding the relative role of this treaty among other sources of international law.