Maritime zones and boundaries

The Netherlands has several maritime boundaries. These boundaries delimit maritime zones and bestow specific rights on the Netherlands. This includes the rights to exploit natural resources and to inspect maritime traffic.

Different types of maritime zones

There are different types of maritime zones in the sea areas of the Kingdom of the Netherlands, in the North Sea and in the Caribbean Sea. The division into maritime zones is made according to the United Nations Convention on the Law of the Sea (UNCLOS). This Convention specifies the following zones:

  • the territorial sea (up to 12 miles off the coast);
  • the contiguous zone (between 12 and 24 miles off the coast);
  • the exclusive economic zone (up to 200 miles off the coast);
  • the continental shelf (the sea bed).

The Kingdom of the Netherlands has established all zones both in the North Sea and the Caribbean Sea.

Normal baselines and straight baselines

The baseline is the line that divides the territorial sea and internal waters. Baselines play a central role in UNCLOS,  as they form the basis for the maritime zones. There are 2 types of baselines:

  • Straight baselines

These have been established by law. Straight baselines indicate the division between internal waters and the territorial sea. The Netherlands established straight baselines in the Territorial Sea (Demarcation) Act in 1985.

  • Normal baselines.

A normal baseline lies where the sea retreats at low water (low water line). These 0-metre depth lines are published in the official nautical charts of the Hydrographic Service. It concerns the most recent charts at a scale of 1:150,000 or larger, or their digital equivalent.

Changes in maritime zones

The Hydrographic Service produces the nautical charts that define the baselines. As a consequence, the Hydrographic Service maintains the locations of the maritime zones. This is because the baseline, and thus the zones, change when a new 0-metre depth line appears in the nautical charts. For example, the construction of Maasvlakte 2 pushed the Dutch coastline westward. Consequently, the Netherlands gained 55 square kilometres of territorial sea.

The Hydrographic Service publishes these changes. This is done by means of Notices to Mariners and a mailing list. You can subscribe to the mailing list by sending an email to: info@hydro.nl.

  • Make sure to write ‘join mailing list maritime limits’ in the subject line.

International news about maritime boundaries is published by the International Boundary Research Unit (IBRU) of the University of Durham. International treaties and national maritime claims are published on the Maritime Space website of the Division of Ocean Affiairs and the Law Of the Sea (DOALOS) of the United Nations.

Delimitation of overlapping zones between countries

The maritime zones of neighbouring countries frequently overlap. In these cases, states can negotiate a treaty in which  the exact location of their mutual maritime boundary is agreed. If there is no treaty, UNCLOS specifies that a line needs to be used at an equal distance between both coasts. This is called the equidistance line.

Changes in 2018

Changes in 2017

Changes in 2016

Changes in 2015