Carbon sequestration has become indispensable to achieving the sustainability objectives set out in the United Nations Framework Convention on Climate Change (UNFCCC) and the Paris Agreement, within the framework of the concept of ‘net zero’ emissions targets. It includes different prospective techniques, which are nonetheless still in their infancy and not easy to implement. This contribution focuses specifically on carbon sequestration at sea as a test case, aiming to underscore the pros and cons of these measures. It is argued that implementing carbon sequestration at sea requires a cooperative approach, within a context whereby climate change necessitates a synergic rethinking of the Law of the Sea.