Abstract The transportation of liquefied natural gas by sea has a strategic function for ensuring the energy security of Poland and, in a broader perspective, also of the countries in the Central and Eastern Europe region (primarily the Visegrad Group - V4 and others). The article points out the importance of Polish LNG/FSRU terminals in diversification and building the region's energy independence. It analyzes the security environment of the Baltic coastal waters, which is the arena for the activity of many countries with different multidimensional interests. A package of threats to maritime critical infrastructure facilities (LNG/FSRU terminals) and cryogenic tankers in the air, surface, and underwater domains is identified, noting the dynamic nature of many of them. The author analyzes the capabilities (strengths and weaknesses) of autonomous maritime systems (USV, UUV-ROV, UAV) in terms of their use to increase the effectiveness of LNG/FSRU terminal security systems. Possibilities of cooperation and achieving a synergy effect within the combined architecture of USV/UUV-ROV/UAV platforms are also indicated. The article presents a package of missions that autonomous systems can perform to increase the safety of operators and reduce the response time to threats, thus increasing the level of protection. The article presents a vision of a modular USV base platform model as a base element for an autonomous system dedicated to protecting LNG terminal/FSRU infrastructure and cryogenic tankers.