The overall objective of this Maritime Policy pilot project and preparatory action was to develop and test mechanisms for improving maritime awareness by sharing operational information between government departments and agencies responsible for monitoring activities at sea of all Baltic Sea countries. One specific goal was the development of technical interfaces that securely allow for all countries to join in a common situational image containing restricted law enforcement and other information. Achievements: The Maritime Surveillance North (MARSUNO) project's objective was to support the creation of a Common Information Sharing Environment (CISE) by identifying practical solutions to overcome legal, technical and administrative hurdles to cross-sectoral and cross-border information sharing between maritime authorities. Among the project ́s findings:• Cooperation in a complex user environment requires a high degree of harmonized conditions. • Establishing an efficient CISE for all authorities acting in the European maritime domain is crucial for enhancing the efficiency and cost effectiveness of maritime surveillance. • The European Commission plays a crucial role for coordination. • The results will be used in the process towards establishing an Integrated Maritime Surveillance which, in turn, will be part of a CISE.