This article examines the history and current situation of gender segregation in Japanese onsens, or hot springs. It explores the various types of establishments that exist, as well as the benefits and drawbacks of gender segregation. In recent years, there have been efforts to make these establishments more inclusive by offering alternative options such as mixed-gender facilities or private rooms. Ultimately, traditional customs have become less strict due to changing social norms and increasing acceptance towards mixed-gender bathing situations.