The topic of this paper is the analysis of the natural gas supply connectivity of northern and southern Europe, and the role of the Croatian liquefied natural gas terminal in this process. Natural gas has become one of the most important energy sources of the 21st century. In order of development of the liquefied natural gas market, gas has become accessible, competitive and global, especially for energy-dependent countries. Like oil in the 20th century, gas is gaining an increasing political and geopolitical character, especially on the European continent, which is defined by high dependence on imports from Russia. Energy legislation, green energy, gas infrastructure and relations between European countries are challenges that will be clarified in this paper. The possibilities of connecting liquefied natural gas terminals in Poland and Croatia will be defined, as well as their contribution to security of gas supply and the natural gas market. A brief analysis of the gas market in Europe and the impact of liquefied natural gas will be presented. The concepts of energy security, security of gas supply, their challenges and possible solutions will be defined and explained through the legislation and practice of the European Union. It will connect the historical, political and geopolitical determinants that have had and have an impact on the creation of political and economic relations of Central European countries with other countries. Through the emphasis on energy and political security, the importance of connecting gas flows and gas infrastructure will be clarified, especially for Central Europe. Connecting through projects supported by formal structures of the European Union, but also an informal organization that could significantly contribute to the challenges of energy security.