The aim of the 2015 Paris Agreement to stay well below a two-degree Celsius increase in the current century will likely not be achieved with solely relying on a reduction in global emissions of carbon dioxide. According to most calculations, it is indispensable to actively remove carbon dioxide from the atmosphere. These forms of climate intervention have often received a lukewarm welcome because of the many uncertainties that surround them. A largely prohibitive approach to these activities to protect the marine environment on the one hand, whenever carbon dioxide removal takes place here, might not always enable the achievement of the goals that humankind set itself in the international regulation of anthropogenic climate change. There is a clear need to bring the protection of the marine environment and climate change mitigation in line with each other. From an international regulatory perspective, this alignment is necessary both at the research stage as well as for large-scale application because international (or regional) rules might form the basis for national legislation on marine carbon dioxide removal. This paper will set out the applicable legal regimes, focusing on the law of the sea, and will outline considerations to be made for legislation to be either prohibitive or enabling.