This article explores the relationship between the Commission on the Limits of the Continental Shelf (CLCS) and dispute settlement tribunals under Part XV of the United Nations Convention on the Law of the Sea (UNCLOS). While the CLCS is tasked with examining scientific claims for continental shelf extensions beyond 200 nautical miles, only Part XV tribunals can settle disputes between States over maritime boundaries.
In several cases, tribunals have been asked to rule on boundary delimitation before the CLCS has issued its recommendations. This raises an important legal challenge. To address this, tribunals like ITLOS and the ICJ have applied the ‘significant uncertainty’ test — they will proceed only if there’s no major doubt about the existence of a continental margin.
Jurisprudence has evolved from early refusals to assert jurisdiction to more recent decisions where tribunals have delimited extended shelves. These decisions show a growing acceptance that delimitation can occur if scientific evidence is strong enough. Still, concerns
remain: acting without CLCS recommendations may weaken its authority or create conflicts. Therefore, tribunals generally treat their assessments as provisional, pending the CLCS’s final evaluation.
