The Sea Basin approach aims at implementing CISE by different authorities from the same sea basins around Europe (i.e., Adriatic Sea, Baltic Sea, Black Sea, Western, Central and Eastern Mediterranean Seas, North Sea, Atlantic Ocean) to address their common maritime threats (as for example: threats to the critical infrastructures, hybrid threats, drug trafficking, unexploded ordnance, disasters at sea, etc.). In the framework of the Sea Basin approach, the interested stakeholders representing different counties and maritime sectors develop and implement operational scenarios to tackle the identified threats with the help of CISE.