Purpose— To consider whether sea- level rise entails the alteration of the baselines, outer limits and boundaries that define the geographical scope of maritime areas. Approach— Drawing from the principle of finality and stability of boundaries and the concepts of ambulatory, geographically fixed and permanent lines, the paper begins with boundaries and continues with baselines and outer limits defined by physically changing natural features. Findings —The fixing of baselines, the delineation of outer limits and the delimitation of boundaries are legal acts that occur at precise moments in time, and which must be assessed based on the coastal configurations existing at those times. Once established and given publicity to, these lines are fixed and permanent. Unless coastal States have intended otherwise, baselines, outer limits and boundaries do not adjust automatically to recession and can only be moved if it is later decided to move them. With regard to anthropogenic change, there are additional reasons supporting the preservation of these lines. Practical Implications— The paper demonstrates that the law of the sea does not make climate change worse. The legal problem can be resolved through interpretation of UNCLOS.