This chapter first appraises the rules of international law that are applicable to disputed territorial sea areas. Article 12 1958 CTS, whose wording is essentially repeated in Article 15 LOSC, provides as follows: historic titles and special circumstances allow States to extend their claim beyond the equidistance boundary; in the absence thereof, the equidistance boundary divides the area of overlapping territorial sea claims. At UNCLOS III, only limited debates occurred in relation to disputed territorial sea areas. As Article 15 LOSC is limited in its sphere of operation once a State invokes historic title or special circumstances, the following question arises: do other rules of international law exert their influence either alongside the interim rule contained in this provision; or when it is inapplicable, what alternative rules can be invoked as a substitute in disputed territorial sea areas? Disputed contiguous zones areas may arise outside the 12 nautical miles limit of the territorial sea. Whereas the issue of an interim rule for overlapping contiguous zone claims was addressed in Article 24(3) 1958 CTS, stipulating that the entitlements of States to a claimed contiguous zone would automatically extend up to the equidistance boundary, the LOSC abandoned this approach.

This chapter examines Article 6 1958 CSC and Articles 74(3) and 83(3) LOSC with a view towards ascertaining the extent to which these provisions set out a rule governing the conduct of unilateral activities in disputed EEZ and continental shelf areas. Article 6 1958 CSC, is the forerunner to the provision in the LOSC, is developed on the basis of equidistance: States are not entitled to extend their continental shelf beyond the equidistance boundary – that is, assuming there are no special circumstances. Articles 74(3)/83(3) LOSC lays down two obligations that are geared towards two different purposes: cooperation and abstention. The cooperative aspect is formed by the fact that States must seek provisional arrangements. The aspect of abstention is exemplified in that the States concerned must refrain from unilateral conduct that hampers or jeopardises EEZ/continental shelf delimitation. These two obligations arise conjointly in some, but not all, disputed EEZ/continental shelf areas. A dual function underlies the obligation not to hamper or jeopardise: first, it places limitations on the scope for coastal States to actively undertake unilateral acts; and, second, the obligation curtails the ways in which States can respond to activities undertaken in a disputed area.