Subjective cognitive decline is a symptom that may appear in the early stages of Alzheimer’s disease. This study examined the effects of smartphone-based calendar training and walking exercise regimen on postmenopausal women experiencing subjective cognitive decline. Experimental group 1 participated in both calendar training and walking exercise, group 2 participated in calendar training only, and the control group did not receive either intervention. Forty-two participants completed a cognitive function test and questionnaire upon entering the study and 12 weeks later. The controlled oral word association score increased in experimental groups 1 and 2 and decreased in the control group. Memory contentment increased in experimental group 1, maintained in experimental group 2, and decreased in the control group. Smartphone-based calendar training and a walking exercise regimen improved executive function and memory contentment in everyday life, but the effects on depressive symptoms and self-esteem were not significant. Our findings demonstrate that smartphone-based calendar training and walking exercise improved cognitive function and have potential as nonpharmacologic interventions to strengthen cognitive function in women experiencing subjective cognitive decline.