The deployment of renewable energy technologies represents a key pathway for exploiting offshore resources and supporting the transition toward sustainable power generation. In this context, floating offshore structures enable energy extraction in deep-water environments where conventional fixed systems are not feasible. This study develops a data-driven assessment of the renewable energy potential associated with floating offshore structures in European seas and proposes an integrated framework for evaluating their sustainable design. The analysis is performed using a curated dataset of European offshore energy projects, incorporating installed capacity, spatial distribution, and technology-specific development indicators. A statistical methodology is applied to quantify regional variability and to identify dominant trends in the deployment of floating renewable technologies. The results demonstrate a rapid increase in floating offshore wind capacity, alongside the emergence of floating photovoltaic systems and hybrid wave–wind–solar configurations. Significant regional disparities are identified in terms of technological maturity, project scale, and growth rates. In addition, a set of sustainability indicators is defined and applied to assess key design aspects of floating structures, including material efficiency, life cycle performance, and environmental impact mitigation. The analysis further evaluates the integration of circular economy principles within current design practices. The proposed approach enables the identification of performance gaps and technological constraints, providing a quantitative basis for optimizing future floating offshore systems. The results support the development of more efficient and sustainable design strategies tailored to European offshore conditions.