In this study, a wrist protector was manufactured and designed using 3D printing technology to prevent wrist pain when riding a bicycle with a high forward-tilted saddle. The efficiency of the design was analyzed in objective and subjective evaluations. First, seven women in their twenties selected their most preferred design by subjective evaluation from among three 3D wrist protectors. Then electromyography (EMG) was measured and subjective sensations were evaluated while wearing and not wearing the preferred 3D wrist protector as selected by cyclists. Experimental results showed that a wrist-bending angle of 30 degrees was most favored. When the 3D wrist protector was worn, muscle activity was smaller at the flexor carpus radialis position than when the 3D wrist protector was not worn; muscle fatigue was also lower. In the subjective evaluation, the 3D wrist protector was more comfortable than no protector, and wrist fatigue was also lower. In addition, the wrist protector was rated positively for its design suitability, size adequacy, ease of operation, and fit; however, cyclists felt that a little more cushioning was needed.