Photovoltaic solar energy has grown significantly in recent years, establishing itself as a key source of renewable energy due to cost reductions and improvements in efficiency. In this context, floating photovoltaic technology emerges as an innovative solution to utilize aquatic spaces, optimize land use, and reduce land occupation, while addressing operational challenges that arise for this new technology. This study compares a floating photovoltaic system with a rooftop system during a 73-day experimental campaign, analyzing their energy performance and the influence of environmental conditions. The results show that the floating system, benefiting from the natural cooling effect of water, improves its energy efficiency by 1.36% compared to the rooftop system. However, it suffers from 9.61% greater losses due to soiling, which limits its performance. In contrast, the rooftop system demonstrates more stable performance due to reduced exposure to soiling, while the floating system experiences a progressive decline in performance. This study contributes to the advancement of floating solar energy by highlighting its advantages and limitations. It underscores the need to develop effective strategies to mitigate the impact of soiling and enhance long-term performance.