There are 3 main types of baselines: normal, straight and straight archipelagic baselines.

The normal baseline is the basic element from which the territorial sea and other maritime zones
are determined. It is defined as the low water line along the coast, as marked on large-scale
charts of the coastal state.

Straight baselines are defined by straight lines that join points on the coastline which have been selected according to the criteria. They delineate internal waters from territorial seas and other maritime zones.

Straight Archipelagic baselines define the periphery on an island group by joining the outermost islands with a succession of straight lines.