The selection of an optimal transport mode in modern logistics systems represents a complex multi-criteria decision-making problem requiring the simultaneous consideration of economic, operational, and environmental factors. This study applies the Fuzzy Analytic Hierarchy Process (Fuzzy AHP) method to determine the weighting coefficients of evaluation criteria and rank alternative freight transport solutions. The analysis focuses on containerized freight flows, considering road, rail, and inland waterway transport as the main alternatives, evaluated according to transportation cost, delivery time, CO₂ emissions, and reliability. A key contribution of the study is reflected in the comparative analysis of three shipment scenarios with different cargo volumes (10, 100, and 500 TEU), enabling a systematic assessment of the influence of shipment size on transport mode selection. The obtained results indicate that increasing cargo volume improves the competitiveness of rail and inland waterway transport due to economies of scale, particularly in terms of cost efficiency and environmental performance, while road transport maintains an advantage primarily in delivery time. The findings confirm the applicability of MCDM approaches in sustainable transport planning and logistics decision-making.