Balance is a fundamental component of motor development that supports posture stability, coordination, and movement efficiency in elementary school children. However, limited physical activity and insufficient balance-oriented learning stimulation often result in suboptimal postural control during middle childhood. This study aimed to determine the improvement in students’ static and dynamic balance after implementing a structured “Flying Duck” game intervention, based on the hypothesis that game-based learning significantly enhances posture stability.A quantitative quasi-experimental method with a one-group pretest–posttest design was applied to 27 third-grade students (Class III A) at SD Negeri 1 Guntung Manggis. Balance performance was measured using the Standing Stork Test for both right and left legs before and after a four-week intervention. Data were analyzed through descriptive statistics, Shapiro–Wilk normality testing, homogeneity testing, Wilcoxon Signed Rank testing, and N-gain analysis. Results showed a substantial increase in mean balance scores, with right-leg performance improving from 5.27 seconds (pretest) to 13.74 seconds (posttest) and left-leg performance from 5.70 seconds to 9.38 seconds. The Wilcoxon test indicated statistically significant differences (p = 0.000 < 0.05). The mean N-gain score reached 32.41% (right leg, moderate category) and 14.87% (left leg, low–moderate category). These findings confirm that systematically designed game-based interventions effectively stimulate neuromuscular adaptation and improve postural control. Integrating structured balance games into physical education curricula is recommended to support fundamental motor skill development in elementary school students.