ABSTRACT Despite the potential cost reduction and environmental friendliness of inland lock waterways, there is a noticeable lack of scientific research on their efficiency and performance. Moreover, empirical insights into the impact of waterway locks on logistics systems are insufficient. Similarly, despite extensive research on data envelopment analysis (DEA) in various logistics contexts, the efficiency of waterway locks remains underexplored. This study addresses these gaps by evaluating inland waterway transposition efficiency based on operational aspects and handling capacity. In this study, data from nine primary inland waterway locks in an emerging economy were examined, comparing their relative efficiency by input-output relationships. Efficiency indices, performance objectives, benchmarks, composite efficiency, and separability conditions were calculated and analyzed. Our results highlight external factors like vessel numbers and volume as efficiency influencers. The study uncovers strategies to enhance efficiency, mainly through operational improvements or leveraging performance indices from other units. Empirical findings present opportunities to optimize maritime logistics operations, especially in countries with expansive territories. This is a novel research that introduces efficiency analysis models for inland waterway locks and offers actionable insights for an underexplored research area. Lastly, the article offers promising research opportunities for maritime logistics systems’ performance.