Baselines

How It Works in Practice

In international law, baselines serve as the starting points from which a coastal state measures the breadth of its territorial sea and other maritime zones. These baselines typically follow the low-water line along the coast as marked on officially recognized charts. From these lines, a state can claim maritime zones such as the territorial sea (up to 12 nautical miles), contiguous zone (up to 24 nautical miles), exclusive economic zone (up to 200 nautical miles), and continental shelf rights.

There are different types of baselines, including normal baselines, straight baselines, and archipelagic baselines. Normal baselines trace the low-water line along the coast, while straight baselines connect appropriate points on the coast when the coastline is deeply indented or fringed with islands. Archipelagic baselines are used by archipelagic states to connect the outermost points of the outermost islands.

Why Baselines Matter

Baselines are fundamental because they define the spatial extent of a coastal state's sovereignty and jurisdiction over maritime zones. The precise location of baselines can significantly affect the size of maritime claims, impacting rights over natural resources such as fisheries and hydrocarbons, as well as security and navigation interests.

Disputes often arise over baseline determinations, especially in areas with complex coastlines or overlapping claims. The United Nations Convention on the Law of the Sea (UNCLOS) provides detailed rules and criteria for establishing baselines to promote consistency and prevent conflicts.

Baselines vs Territorial Sea

It's important not to confuse baselines with the territorial sea itself. Baselines are the reference lines along the coast from which the breadth of the territorial sea is measured. The territorial sea is a maritime zone extending seaward up to 12 nautical miles from these baselines where the coastal state exercises sovereignty. Thus, baselines are the starting line, while the territorial sea is the zone measured from them.

Real-World Examples

A notable example is Norway's use of straight baselines along its deeply indented fjord coastline, which has been internationally recognized and allows Norway to claim an extensive territorial sea. Similarly, Indonesia, an archipelagic state, utilizes archipelagic baselines connecting its outer islands to enclose its waters as internal waters, giving it significant maritime control.

Common Misconceptions

One common misconception is that baselines are always the low-water line along the coast. While normal baselines do follow the low-water line, in certain geographic situations, such as deeply indented coastlines or archipelagic states, straight or archipelagic baselines are used instead. Another misconception is that baselines themselves confer sovereignty; rather, they are a legal tool to measure maritime zones where sovereignty or jurisdiction applies.