This chapter briefly presents major historical trends that led to and informed the content of the rules of today’s law of the sea as reflected in the UN Convention on the Law of the Sea, and identifies some key challenges for the law of the sea as the Earth leaves the Holocene and enters a new epoch in its geological history, the Anthropocene. The law of the sea is a branch of international law that applies to 71 percent of the Earth’s surface area. Present international law of the sea received its frame in the near-universal 1982 UN Convention on the Law of the Sea, which in turn built on some four centuries of development. Challenging the core normative and institutional structures established on these bases would essentially mean challenging international law – which in itself is a relatively recent achievement of human civilization. On the other hand, simply continuing along the same path is, given increasing impacts of human activities on the oceans, hardly a feasible option. Ocean governance and law structures may require profound re-examination of what have become accepted perspectives. With few exceptions, our current rules regulate human impacts on the ocean components of the Earth System in terms of the political bound¬aries of sovereignty and jurisdiction, translated into law. Basically, this is what is expressed through the various maritime zones and the main division of jurisdictional competences among coastal and flag states. However, the ultimate objectives may need to be shifted, and international regulations crafted so as to enable us to channel and confine the human impact on the Earth System – as we enter the Anthropocene, a new epoch in the history of our planet.