The paper presents the principle aspects of key European Union legislation concerning critical infrastructure protection. Fundamental definitions and assumptions covered by the respective documents, with a special focus on critical infrastructure, its identification and protection, are also included. Basic outcomes of the regulations, reflecting other acts of law concerning the rights and obligations of States within their territorial sea and exclusive economic zone, regarding specific matters related to the Baltic Sea area and EU member states located around it, have also been introduced. Some approaches to the modelling of ECI identification is also given, and analysis of the latest EU activities, associated with the adaptation of critical infrastructure systems to climate change predictions, is introduced. As the vulnerability to the impact of climate change is of key importance for systems operating within the Baltic area, essential findings that apply to them are also covered.