Active and meaningful public engagement is necessary to foster informed and publicly accepted natural resource management. Citizen science presents an important avenue by which to achieve such engagement. Citizen science is the active involvement of the public in science to address scientific questions, often of common interest or concern, by collecting and analyzing data, and publishing and communicating science via diverse outlets. Here, we explore whether and how citizen science can also play a role in generating social license for marine conservation, using European marine citizen science as a case study. Social license is a concept that reflects community views and expectations on the use and management of natural resources. To date, social license in the marine space has largely focused on public perceptions of industrial and extractive uses of the marine environment, and limited research has explored social license for conservation. We highlight important linkages between social license and citizen science that can work synergistically to support conservation. We use in-depth qualitative interviews and a semiquantitative online survey of marine citizen science coordinators to investigate how citizen science can play a role in enhancing social license and the mechanisms through which it can occur. Our findings indicate that citizen science can enhance social license by improving ocean literacy and marine citizenship. We demonstrate that marine citizen science has considerable potential to generate and develop social license for marine conservation in Europe and elsewhere.