About 20% of patients with breast cancer are likely to develop breast cancer-related lymphedema (BCRL) following an axillary clearance, and BCRL can be refractory or irreversible to treatment. The aim of this pilot randomized controlled study was to evaluate the effectiveness of a 10-min holistic self-care program for patients with BCRL in Japan. The intervention group (n = 22) practiced the BCRL self-care program including 1) modified Japanese Radio Taiso (Rajio Taiso, national calisthenics in Japan), 2) gentle arm exercises combined with deep breathing, 3) central lymphatic drainage, and 4) skin care using a traditional lymphatic drainage technique daily for 6 months, while the control group (n = 21) received usual care from their hospitals. There was significant group*time interaction in the relative edema volume and relative volume change of the hand, with the intervention group having the better outcome. The intervention group showed significant improvement in transepidermal water loss as well as the mental health component summary score of the SF-8, most of BCRL-related symptoms, self-care time and score, frequencies of exercise, self-lymphatic drainage and skin care, and perceived adherence and effectiveness to self-care, although we were unable to exclude the possibility of the Hawthorne effect. Notably, even in the control group, the self-care was similarly increased, but the significant improvements were detected only in transepidermal water loss on the forearm and upper arm, pain and coldness. In conclusion, the patients who practiced the holistic BCRL self-care for 6 months have shown greater improvement.