Kombucha is a traditional fermented tea known for its health-promoting properties, including antioxidant and antidiabetic activities. Ginger (Zingiber officinale) is widely used as a functional ingredient in kombucha due to its rich phytochemical content. This study aimed to comparatively evaluate the antioxidant and antidiabetic activities of kombucha prepared using three ginger varieties—elephant, emprit, and red ginger—during an 18-day fermentation period. Each ginger extract was brewed in sugared black tea (Camellia sinensis), inoculated with a symbiotic culture of bacteria and yeast (SCOBY), and fermented at room temperature. Samples were collected at 0, 6, 12, and 18 days to analyze pH, total acidity, and total sugar content. Antioxidant activity was assessed using DPPH assays, while α-glucosidase inhibition was measured to evaluate antidiabetic potential. Results showed a consistent decline in pH and sugar levels with a concurrent increase in total acidity, indicating progressive microbial activity. Among the variants, elephant ginger kombucha displayed the highest antioxidant capacity and α-glucosidase inhibition, particularly on day 12, suggesting this as the optimal fermentation time for functional efficacy. Differences in activity among the ginger types were attributed to their unique phytochemical profiles, influencing fermentation dynamics and metabolite production. In conclusion, ginger-based kombucha, particularly from gajah variety, emerges as a promising functional beverage with potential health benefits related to oxidative stress reduction, glycemic control. These findings support the potential development of ginger-based kombucha as a functional beverage for managing oxidative stress and postprandial hyperglycemia. © 2025