Difficulties concerning the right of passage through straits and interoceanic canals occur when the two bordering land areas are under the jurisdiction of different countries, or when the straight lies between portions of the land area of the same country but provides the only access by sea to the land of another country beyond the straight. Passage through such straits may be restricted or the strait may be closed under conditions of war or to further economic sanctions. The jurisdiction over straits waters may be subject to dispute, particularly if there is a conflict over the breadth of the territorial water claimed by the states in question.
Approximately thirty straits are considered important routes for international traffic, and there are three major interoceanic canals (Panama, Suez and Kiel).