On 13 July 2023, the International Court of Justice (the “ICJ” or the “Court”) issued its judgment in the case concerning Question of the Delimitation of the Continental Shelf between Nicaragua and Colombia beyond 200 nautical miles from the Nicaraguan Coast (Nicaragua v. Colombia), instituted by Nicaragua against Colombia on 16 September 2013. Nicaragua requested the Court to delimit the boundaries between, on the one hand, the continental shelf of Nicaragua beyond the 200-nautical-mile (“nm”) limit from the baselines from which the breadth of the territorial sea of Nicaragua is measured and, on the other hand, the continental shelf of Colombia.
Before considering any technical or scientific questions with respect to the delimitation, the Court held in its Order of 4 October 2022 that two questions of preliminary character should be resolved:
- First, under customary international law, may a State’s entitlement to a continental shelf beyond 200nm from the baselines from which the breadth of its territorial sea is measured extend within 200nm from the baselines of another State?
- Second, what are the criteria under customary international law for the determination of the limit of the continental shelf beyond 200nm from the baselines from which the breadth of the territorial sea is measured and, in this regard, do paragraphs 2 to 6 of Article 76 of the United Nations Convention on the Law of the Sea 1982 (“UNCLOS”) reflect customary international law?
The ICJ instructed Nicaragua and Colombia to base their arguments on customary international law, which the Court held as applicable to the case because, unlike Nicaragua, Colombia is not a party to UNCLOS.
In its decision, the ICJ only considered the first preliminary question (see paras 35 to 79), noting that its verdict on that question precluded the need for it to address the second question. The Court observed that, as a matter of State practice, the vast majority of States parties to UNCLOS to have made submissions to the Commission on the Limits of the Continental Shelf (“CLCS”) have chosen not to assert outer limits of their continental shelves that extend within 200nm of the baselines of other States. The ICJ regarded this practice as being indicative of opinio juris. The Court therefore concluded (by thirteen votes to four) that, as a matter of customary international law, a State’s entitlement to an extended continental shelf beyond 200nm may not impinge on the rights of another State within its own 200nm limit.
In reaching the above determination, the ICJ confirmed the customary international law nature of various UNCLOS provisions, and consequently their applicability to non-signatory States.
Notwithstanding the ICJ’s determination that Nicaragua’s continental shelf must be maintained at its existing limits, Colombia remains under an obligation to comply with ICJ’s 2012 judgment regarding Nicaragua’s sovereign rights over certain maritime areas.
The dissenting opinion of Judge Charlesworth is here.
The dissenting opinion of Judge Tomka is here.
The dissenting opinion of Judge Robinson is here.
The dissenting opinion of Judge ad hoc Skotnikov is here.
The separate opinion of Judge Xue is here.
The separate opinion of Judge Iwasawa is here
The separate opinion of Judge Nolte is here.
Declaration of Judge Bhandari is here.