Fatigue is a prevalent condition that can impair balance and proprioception, increasing the risk of falls and accidents. The effects of fatigue on balance have been studied, but there is limited research using advanced sensor technologies to assess these effects in real-time. Background/Objectives: This study aims to investigate how fatigue impacts balance and proprioception through mobile sensor technology. Methods: A total of 251 participants (mean age = 19.83 ± 0.94 years) were classified into low (n = 211) and high (n = 40) fatigue groups based on the Fatigue Assessment Scale. Each participant performed the mini-CITSIB (Cognitive and Sensory Integration Balance) test under four conditions: eye open with a fixed surface, eye closed with a fixed surface, eye open with a foam surface, and eye closed with a foam surface. Mobile sensors (accelerometer, gyroscope, linear accelerometer, and magnetometer) were used to record movement and stability data. Key variables calculated included jerk, peak-to-peak, root mean square (RMS), range, standard deviation (SD), and the coefficient of detrended fluctuation analysis (coeff_dfa). Data were analyzed using SPSS software, with independent samples t-tests comparing the fatigue groups for each condition. Results: Significant differences in sensor readings were observed between low and high fatigue groups across all conditions. The high fatigue group showed greater variability in movement and lower values in jerk, peak-to-peak, and RMS, indicating reduced stability and more erratic movements. Coefficients of DFA for rotation and side bending were significantly higher in the high fatigue group, suggesting increased fluctuations in movement.