Social licence is an emergent concept in the marine sector and has become an important theme for development in marine industry and resource use, particularly in the context of exploring communication and stakeholder engagement. At the same time, meaningful public and societal engagement with science and research is increasingly recognised as necessary to advance public knowledge about the marine environment and to promote stewardship of ocean spaces. Citizen science is a diversified phenomenon that is expanding rapidly in marine spaces and may create pathways for support between social groups and promote networks for collaborative decision making that can enhance outcomes for science and management. Our research is among the first attempts to link social licence theory with citizen science, aiming to produce actual practical outcomes that can be applied in ocean management. Here, we examine the role marine citizen science can play in promoting social licence in the marine realm. Firstly, through an exploration of European citizen science projects and their potential to enhance social licence for marine conservation. Secondly, we describe an Australian case- study highlighting whether diverse participant groups (i.e. divers, fishers) construct and exchange opinions via this platform and whether social licence is promoted or withheld through such exchange. We outline the potential role of social licence as a tool to foster positive engagement between marine user groups, and identify how citizen science may influence perceptions and promote social licence in the marine realm.