[1] In 2023, agreement was reached on a High Seas Treaty to be added as an instrument of the convention, to protect ocean life in international waters.

Between 1946 and 1950, Chile, Peru, and Ecuador extended their rights to a distance of 200 nautical miles (370 km; 230 mi) to cover their Humboldt Current fishing grounds.

[16] Generally speaking, developing nations and third world countries participated only as clients, allies, or dependents of the United States or the Soviet Union, with no significant voice of their own.

[9] The issue of varying claims of territorial waters was raised in the UN in 1967 by Arvid Pardo of Malta, and in 1973 the Third United Nations Conference on the Law of the Sea convened in New York.

In an attempt to reduce the possibility of groups of nation-states dominating the negotiations, the conference used a consensus process rather than majority vote.

[20][21] Aside from its provisions defining ocean boundaries, the convention establishes general obligations for safeguarding the marine environment and protecting freedom of scientific research on the high seas, and also creates an innovative legal regime for controlling mineral resource exploitation in deep seabed areas beyond national jurisdiction, through an International Seabed Authority and the common heritage of mankind principle.

[24] Part XI of the convention provides for a regime relating to minerals on the seabed outside any state's territorial waters or exclusive economic zones (EEZ).

The United States objected to the provisions of Part XI of the convention on several grounds, arguing that the treaty was unfavorable to American economic and security interests.

Due to Part XI, the United States refused to ratify the UNCLOS, although it expressed agreement with the remaining provisions of the convention.

From 1982 to 1990, the United States accepted all but Part XI as customary international law, while attempting to establish an alternative regime for exploitation of the minerals of the deep seabed.

Concurrently, the Preparatory Commission was established to prepare for the eventual coming into force of the convention-recognized claims by applicants, sponsored by signatories of the convention.

[25] The advisory opinion was issued in response to a formal request made by the International Seabed Authority following two prior applications the authority's Legal and Technical Commission had received from the Republic of Nauru and the Kingdom of Tonga regarding proposed activities (a plan of work to explore for polymetallic nodules) to be undertaken in the area by two state-sponsored contractors – Nauru Ocean Resources Inc. (sponsored by the Republic of Nauru) and Tonga Offshore Mining Ltd. (sponsored by the Kingdom of Tonga).

The advisory opinion set forth the international legal responsibilities and obligations of sponsoring states and the authority to ensure that sponsored activities do not harm the marine environment, consistent with the applicable provisions of UNCLOS Part XI, Authority regulations, ITLOS case law, other international environmental treaties, and Principle 15 of the UN Rio Declaration.

Part XII also bestows coastal and port states with broadened jurisdictional rights for enforcing international environmental regulation within their territory and on the high seas.

[40][39] Though the agreement does not directly address climate change, it also serves as a step towards protecting the ecosystems that store carbon in sediments.

One of its main aims is "s stewards of the ocean in areas beyond national jurisdiction on behalf of present and future generations by protecting, caring for and ensuring responsible use of the marine environment, maintaining the integrity of ocean ecosystems and conserving the inherent value of biological diversity of areas beyond national jurisdiction".