This note deals with the request of an advisory opinion submitted on 12 December 2022 by the Commission of Small Island States on Climate Change and International Law to the International Tribunal for the Law of the Sea. In this request, this Commission has asked to the Tribunal what the specific obligations of the States Parties to the United Nations Convention on the Law of the Sea are, firstly, to prevent, reduce and control pollution of the marine environment, and secondly, to protect and preserve the marine environment. In this sense, this note analyses the advisory jurisdiction of the Tribunal, considering article 2.2 of the Agreement that establishes this Commission, article 21 of the Statute of the Tribunal and article 138 of Rules of the Tribunal, and also the position of the Tribunal with regards to its advisory jurisdiction on its previous advisory opinion delivered on 2015. In light of the legal questions submitted, the possible substantive answers that the Tribunal could give in case it finds itself competent are considered, too. Lastly, the note concludes with several final remarks.