The Blue Economy is a crucial research topic. Covering 70 percent of the Earth, the oceans have an important role in climate regulation. They provide a substantial part of the world’s population with food and a source of income. Since the 1950s, maritime transport has been the backbone of global trade development. The Blue Economy is complex and includes a plurality of ocean-related economic sectors and dimensions (marine engineering, aquaculture, fisheries, ecotourism, marine biosciences, etc.) that could attract more and more multinational enterprises. The marine and coastal environments are an important source of economic growth; worldwide turnover is around 1,500 billion USD per year. Oceans also offer vast potential for renewable energy production. Caring for the Blue Economy is therefore essential in the context of an overall approach to sustainable development. Given this situation, the aim of the chapter is to show how a maritime cluster can positively impact the Blue Economy and its growth with an idea of sustainability. The research is founded on the case of the Luxembourg Maritime Cluster (LMC), established in 2008. The field of study is of particular interest because the cluster is located in a landlocked country. Using a qualitative approach, the research identifies different dimensions impacted by the action of the cluster. It shows that some elements of the Blue Economy are more impacted than others due to the influence of the cluster organization and the particularity of its relationships. It seems that the variety of current members of the cluster, the structure of the LMC, and the quality of relationships facilitate international business developments and unique innovation processes with a sustainable view in certain fields of the Blue Economy.