The Master’s Thesis examines how democratic participation in governing the ocean can increase sustainability. Thus, the Thesis is based on the EU´s Directive of Maritime Spatial Planning and Denmark's first Maritime Spatial Plan. Critical Theory is applied as the overall theoretical perspective. In addition, Governing the Commons is used to explain cooperation among stakeholders when governing common natural resources. Furthermore, Deliberative Democracy and Marine Citizenship are applied to explain how increased democratic participation in governing the ocean can increase ocean sustainability. The analysis is based on semi-structured interviews with actors from the UNESCO IOC, the Danish Maritime Authority, and WWF, respectively. In addition, secondary empirical data is used, including the Consensus Conference Our Ocean, a citizen participation process, which was held in Oct. 2020. The analysis indicates that the mediums of money, hierarchy, and power, including avoidance, are present in the process of developing Denmark’s Maritime Spatial Plan and because indication shows insufficient democratic participation among relevant actors, which might have led to a lower support among politicians, business and interest organizations, NGOs, and researchers. Furthermore, the analysis indicates that because the consequences are so enormous, the general population must understand why it is essential to ensure a healthy ocean. The Consensus Conference demonstrated that when citizens become involved in complex problems, they can, through increased literacy, form and develop their opinions and that increased literacy can foster a change in values and behavior. Moreover, the analysis indicates a lack of understanding of how the planning and execution of citizen participation processes affect the results. Thus, the analysis shows that planning needs to work within a wicked planning framework.