Skin diseases associated with athletic activities can be classified as skin infections, inflammatory reactions, trauma, and abnormal proliferation, depending on the cause of the condition. Athlete's nodule is a generic term for reactive nodules that occur in athletes. It is particularly common in the foot due to tight sneakers, repetitive pressure or friction, and inappropriate choice of shoes or other sports equipment. The diagnosis of black heel (calcaneal petechiae) should be considered when numerous black spots occur on the soles in patients who frequently engage in abrupt movements, such as starts, stops, or leaps. Palmoplantar eccrine hidradenitis may occur in athletes who play baseball, dance, and climb, activities in which repetitive and strong stimuli are applied to the floor of the hands and feet. Painful fat herniation should be suspected in cases of painful skin-colored firm nodules on the feet of athletes who place a large amount of weight on their feet when moving. Itching, urticaria, angioedema, chest tightness, and syncope occurring within 5 minutes after starting exercise should be suspected to be exercise-induced angioedema/anaphylaxis. Excessive force can cause deformation of nails, as in tennis toe and jogger's toenail. For the diagnosis and treatment of sports-related skin diseases, it is essential to pay attention to patients' hobbies and exercise habits, including sports, and to consider the relationship of those habits with the presumed mechanisms of the skin disease. In addition, thorough pre-exercise warm-ups, increasing strength gradually, and wearing proper equipment will help prevent the occurrence of sports-related skin diseases.