The Finnish straight baseline system has been printed on large-scale charts published by the Finnish Hydrographic Office. The most recent editions, which have been examined by this office, were printed in 1965.
The law contains three interesting concepts. First, the system is subject to a periodic review. According to Article 4(3), the points must be corrected at intervals of 30 years. Second, the Government of Finland has commenced its straight baseline system by connecting Swedish and Finnish islets; the intersection of this line with the Finnish-Swedish maritime frontier marks the beginning of the Finnish system. This unusual technique has been employed by several North European states.
The third, and most important, concept is stated in Article 4(2) which provides that the basepoints will be chosen so that their [basepoint] distance from one another is at most twice the width of the marginal sea….” As a consequence, the longest Finnish straight baseline segment measures 8 nautical miles or less in length, a restriction which contrasts sharply with the practices of many states. The limitation of the length of baseline segment means that the Finnish system nearly duplicates the configuration of the fringing islands. The Finnish system is the least expansive straight baselines yet analyzed by this office.
The total length of the Finnish system measures approximately 793.2 nautical miles between the Swedish and Soviet maritime frontiers. The average length of a segment is approximately 4.4 nautical miles.
Finland is a party of the Convention on the Territorial Sea and Contiguous zone.