Groin pain in athletes is a complex diagnostic and therapeutic challenge. Sports hernia is one of the common causes of groin pain. We report a case of sports hernia, initially presented as groin pain and aggravated by sports activity. A 19-year-old soccer player visited the outpatient department of general surgery and was referred to the rehabilitation center due to no abnormalities detected in the abdomen and pelvis by computed tomography. An incipient direct bulge of the posterior inguinal wall was detected with dynamic ultrasound when abdominal tension was induced by raising both legs during a full inhalation. Surgery was performed and preoperatively both groins showed the presence of inguinal hernia. Diagnosing sports hernia is very challenging. Through careful history documentation and physical examination followed by dynamic ultrasonography, we identified his posterior inguinal wall deficiency for early management.