The UN Ocean Decade brings about a noticeable upswing of requests for advisory opinions from international judicial bodies – potentially promising to be an effective tool to develop the Law of the Sea. In the light of new challenges in environmental law, such as climate change and sea level rise, advisory opinions ought to provide an operative way for States to seek clarification on legal questions, without needing to threaten their political relationships by suing another State. For Law of the Sea matters, the advisory jurisdiction of its special judicial body has been contested profoundly. Whether advisory opinions as a tool to develop the Law of the Sea through the International Tribunal for the Law of the Sea will experience a boom, hinges upon the question to what extent ITLOS enjoys advisory jurisdiction. Using the means of interpretation under the Vienna Convention for the Law of Treaties, this article argues that ITLOS possesses advisory jurisdiction.
