As global demand for sustainable protein rises, Wolffia globosa has emerged as a promising "future food." However, its environmental viability regarding water use remains under-researched. This study evaluated the Water Footprint (WF) of W. globosa across two production models in Thailand: an open natural pond and a controlled closed system, utilizing Water Footprint Network standards and CROPWAT 8.0. Results showed a stark contrast in efficiency; the open system exhibited a high total WF of 1,615.62 m³/ton due to significant evaporation and seepage. Conversely, the closed system demonstrated superior efficiency with a total WF of only 196.06 m³/ton an 87.86% reduction. Furthermore, grey water footprints were nearly 50% lower in the closed system, reflecting enhanced nutrient management. Transitioning to closed-system models is essential to optimize water productivity and provide a scalable, sustainable pathway for aquatic protein production.