Key takeaways:

• On 27 January 2014, the International Court of Justice (“ICJ” or “Court”) delivered its judgment in the maritime boundary dispute between Peru and Chile. The Court held that the maritime boundary between the two States had been defined by a tacit agreement between the Parties in or before 1954 and that it extended to a distance of 80 nautical miles along a parallel of latitude. Since the agreed boundary covered only a portion of the relevant maritime area, the Court proceeded to delimit the remainder of the maritime boundary in accordance with the established equidistance method.
• The finding that a tacit maritime boundary agreement was in existence - a thesis which had not been advanced by either Party - succeeded in reconciling the States’ competing claims and effectively divided the contested maritime area equally between the Parties. However, the solution provoked judicial discussion about whether the standard of evidence required to establish the existence of a tacit boundary agreement had been met in the present case.