Introduction. We compared of lower extremity dominancy, subtalar angle, balance, fall risk, and performance in younger adults with and without pes planus. Methods. A total of 80 physically active subjects participated. 39 patients with flexible pes planus, 41 asymptomatic participants. Arch height of subjects was assessed by the navicular drop test, the subtalar joint angles were assessed by the goniometer, balance assessments were performed by the Biodex Balance System, and performance assessments were performed by the single-leg jump, and vertical jump tests. Furthermore, the strength of the gluteus medius muscles was measured by a dynamometer. Results. A significant difference was demonstrated for the subtalar angles (right and left), single-leg jump, and vertical jump tests of asymptomatic subjects and subjects with pes planus (p < 0.05). Conclusions. It can be concluded that there was a decrease in subtalar angle and performance in young adults with pes planus compared with asymptomatic subjects. These suggest we take prophylactic measures before the effects are seen in young adults.