Type 2 diabetes (T2D) is associated with increased risks of morbidity and mortality. Diabetes prevention is an urgent issue in Japan. The Finnish Diabetes Prevention Study and US Diabetes Prevention Program revealed that intensive lifestyle intervention can prevent or delay the development of T2D in high‐risk populations. Translational research varies in hospitals, primary care, communities, the workplace, and other settings. Translational research is feasible but less effective. There have been no long‐term follow‐ups. The outcome of the studies was mainly weight changes. The Japan Diabetes Prevention Program (JDPP) is a trial to test the efficacy of a lifestyle intervention program, which carried out in a primary healthcare setting using existing resources. The Japan Diabetes Outcome Trial‐1 (J‐DOIT1) is a nationwide telephone‐delivered lifestyle intervention in a real‐world setting. This review will focus on the effectiveness of a diabetes prevention program (recruitment, target population, method of intervention, and evaluation) in the real world and insights from the JDPP and J‐DOIT1.