When commercial sea harvesters have dive accidents, it is sometimes difficult to obtain an accurate dive history and make a definitive diagnosis. We report a sea harvest diver who dived to collect sea snails (Rapana venosa) by using a hookah dive system. He experienced mediastinal and subcutaneous emphysema due to interruption of breathing airflow. Thoracic computed tomography performed one year prior to the accident revealed paramediastinal subpleural blebs on both lung apices. Emphysema was resolved by administering normobaric oxygen.