The aim of this work is to analyze the development of alternative ship propulsion systems with an emphasis on future trends in shipping. This research was prompted by a number of factors, including the uncertain availability and rising prices of fossil fuels, whose negative impact on the environment is becoming increasingly apparent. In addition, legal restrictions are increasingly encouraging the industry to explore and implement alternative propulsion technologies. The paper compares currently used technologies in the maritime sector, investigating their advantages and disadvantages. The types of alternative energy discussed in this paper are: fuel cells, batteries, biofuels, hydrogen, ammonia, methanol, wind energy and solar energy, and liquefied natural gas. For each type of alternative energy, the economic, ecological, technical and social impacts are described in detail in order to gain a complete insight into their application. Special attention is paid to the application of alternative propulsion systems in the area of the Adriatic Sea. The availability and possibility of applying certain types of alternative plants in the Republic of Croatia is being investigated. This work aims to provide a thorough understanding of the current trends and future perspectives of alternative marine propulsion systems, with the aim of contributing to a more sustainable future of shipping and reducing the negative impact on the environment.