Wetlands are among the most productive ecosystems worldwide, and zooplankton, as key components of freshwater systems, represent potential natural sources of antioxidant compounds. This study aimed to evaluate the antioxidant capacity of wild zooplankton from the Hana Dam Lake during different seasons. Sampling was conducted from three wetland zones at depths of 4 to 22 meters during four seasons, and antioxidant activity was measured using DPPH, FRAP, and ABTS assays. In the DPPH method, the highest antioxidant activity occurred in summer using acetone and ethanol (0.84% and 1.85%, respectively), while the lowest values were recorded in spring with acetone (8.72%) and in autumn with ethanol (8.47%). In the FRAP assay, maximum antioxidant levels were observed in spring with acetone and ethanol (7.8% and 9.7%), whereas the lowest values were obtained in summer with acetone (2.2%) and in autumn with ethanol (3.9%). Using the ABTS method, the highest antioxidant activity was observed in winter with acetone (7.97%) and in autumn with ethanol, while the lowest levels were detected in summer (3.78% and 9.93% for acetone and ethanol, respectively). Among the assays, ABTS proved to be the most sensitive technique. Statistical analysis was performed at a significance level of p < 0.05. Overall, the findings highlight the pivotal roles of seasonality, solvent type, assay method, and environmental conditions in determining the antioxidant capacity of zooplankton. The study underscores zooplankton as rich sources of natural antioxidant compounds with promising applications in pharmaceutical, food, cosmetic, and biotechnological industries, contributing to the development of sustainable natural products.