The key treaty on the law of the sea is the UN Convention on the Law of the Sea 1982 (LOSC). LOSC largely reflects customary international law.

The regulation of the oceans reflects a compromise between, on the one hand, exclusive claims to maritime dominion on the part of coastal States and, on the other, inclusive claims to the reasonable use of the oceans on the part of the international community as a whole.

The history of the law of the sea has been marked by doctrinal controversy and the tensions between the two divergent regimes of mare clausum, namely the idea of maritime dominion, and mare liberum, ie the freedom of the seas.

The legal order of the oceans ascribes jurisdictional competences to coastal States and flag States. The countries where vessels are registered (flag States) possess a significant amount of competence over these and their crew in all maritime belts. Likewise, countries with maritime territory (coastal States) possess significant competences of regulation and enforcement therein.

Coastal States enjoy broad competences in certain maritime belts (namely internal and territorial waters), which is expressed with the term sovereignty. In other maritime belts, including the continental shelf and the EEZ, they enjoy limited competences. These are denoted by the term sovereign rights.