The current study aimed to examine the effectiveness of multimedia messaging service (MMS) education on exercise benefits and barriers in patients with type 2 diabetes. A quasi-experimental, pretest-post-test design recruited 98 patients with type 2 diabetes. The intervention group received MMS education to improve perceived exercise benefits and decrease exercise barriers over two months, and the control group received routine care. All patients completed a survey at three time points (baseline, 4 and 8 weeks post-intervention). The results showed that there was an improvement in both perceived life enhancement and physical performance domains in the intervention group. The exercise context barriers decreased after the first follow-up but increased during the second follow-up in the intervention group. Cohen's d values indicated a medium effect size in life enhancement (0.502) and physical performance (0.525) subscales. A small effect size was found in psychological outlook (0.196) and exercise context (0.132) subscales. However, there was no significant effect of the intervention in time expenditure (-0.244) and physical exertion (-0.119) subscales. In conclusion, theoretically based MMS health education targeting perceived exercise benefits and barriers was feasible and cost-effective in changing patients with diabetes' perceptions and intended behaviors about regular physical activity.