The maritime boundary between the Caribbean Sea Island nation of Antigua and Barbuda and Anguilla, an overseas territory of the United Kingdom, was established on 27 July 2021 following two rounds of bilateral negotiations. The boundary extends for 177 nautical miles and is formed by a series of geodesic line segments that connect the southern tripoint with the French Collectivity of Saint Martin to the Parties’ 200 nautical mile exclusive economic zone limit in the northeast.

Antigua and Barbuda and the United Kingdom agreed to construct the boundary line using a strict application of the equidistance methodology.