It seems clear that the impacts of sea level rise were not contemplated by the drafters of the 1982 Law of the Sea Convention during UNCLOS III (1973-1982). Legal scholars began to identify these issues in the early 1990s but the establishment and work of the International Law Association (ILA) Committee on International Law and Sea Level Rise has since 2012 drawn increased attention to the importance of this issue that is now being considered also by a Study Group of the UN International Law Commission (ILC) established in 2019. This article traces the remarkable and swift evolution over the last decade of state practice on the interpretation of the relevant provisions of the Law of the Sea Convention in relation to the impacts of sea level rise on baselines and limits of maritime zones. This rapid evolution in state practice provides an interesting case study of the ability of the Convention, now at forty, to adapt to new situations and challenges.