In this thesis, the Croatian fleet of small coastal fishing vessels was analysed. The annual carbon footprint of the Croatian fleet of vessels up to 12 meters in length was calculated. Using the example of one vessel, Life Cycle Assessment (LCA) and Life Cycle Cost Assessment (LCCA) were conducted for a lifespan of 30 years. The solutions considered were a fully electric vessel, a hybrid electric vessel, a vessel powered by Liquefied Natural Gas (LNG), biodiesel, and a vessel powered by methanol. The proposed solutions were then compared with the reference diesel engine. For a better understanding of the proposed solutions, investment return analyses and sensitivity analyses on fuel price changes were also conducted. According to current law, the carbon tax only covers ships over 5000 gross tonnage. Considering that the vessel is observed over a period of 30 years, during which the law may change, an LCCA analysis was also conducted in the case of the introduction of a carbon tax. The LCCA results show that the diesel vessel is the most cost-effective, but the other solutions deviate relatively little. The LCA indicates that a fully electric vessel is the most environmentally friendly alternative solution, with 57% fewer emissions than diesel over a period of 30 years, with only 3% higher costs. Despite this, due to high annual costs and potential issues with the weight and placement of the battery, methanol propulsion stands out as the most suitable. It causes 36% fewer emissions than diesel for 5% higher lifetime costs, with a good annual cost profile. The results obtained from the conducted analyses should serve as a guideline for the further establishment of the vessel's energy system, with a more detailed insight into the construction and form of the vessel, sailing regimes, and port infrastructure.