He was a judge of the International Tribunal for the Law of the Sea (1996-2011) and President of its Seabed Disputes Chamber. He was a counsel of different states in international courts and tribunals, consultant to various governments and international organizations. Judge Treves is also a member of the Curatorium of The Hague Academy of International Law since 2010 and previously taught at the Academy. He is a member of many learned societies including Institut de Droit International and author of numerous books and articles on international law, including on the international courts and tribunals.