This chapter analyses the preconditions for increasing cross-border inter-cluster cooperation in the maritime and energy sectors in the Eastern Baltic Sea region (i.e. Estonia, Finland, Latvia, Lithuania, and North-West Russia). The chapter describes the recent developments and cooperative connections in both sectors, after which it is concluded that room for increased cooperation exists, particularly in terms of green solutions. Such international cooperation still remains modest due to detrimental factors, national state interests being the most evident in both the sectors. Therefore, political support is of great importance in increasing inter-cluster cooperation, which can result in innovative discoveries, new business networks, and increased competitiveness to the region's key industries.