Aquasoya, or soybean cooking water, is a novel plant-based material as an egg substitute due to its functional proteins. However, research on its fermentation is still emergent. To assess its prebiotic potential, we developed a plant-based yoghurt alternative using aquasoya powder (ASP). After analysing the main components of ASP, six variants of aquasoya yoghurt, employing commercial cultures, underwent physicochemical, rheological properties, lactic acid bacteria viability and sensory attributes. The results showed that all samples were maintained under pH 4.6 and acidity over 0.7 for 20 days of storage and displayed prebiotic potential. Additionally, yoghurt with 8% ASP content and Sacco starter culture exhibited a thinner network phase. Panellists noted yoghurt with culture – Culture For Health – had weaker flavour intensity and yoghurt with 8% ASP received the highest overall liking score in the preliminary consumer acceptance test. This study established aquasoya as a promising food ingredient for incorporation into a novel milk substitute.