To date, more than 1,000 species of barnacles have been reported, and some barnacles spend most of their life attached to marine vertebrates. As their distribution patterns are as diverse as their species diversity, they can be important data for understanding the behavior or ecology of host organisms as epibiont. However, in Korea, further research is needed because studies on the relationship between barnacles and marine vertebrates are still insufficient. In this study, we report a barnacle attached to a Chinese sea krait (Laticauda semifasciata) caught in the sea of Korea. On September 7, 2016, in the sea near Udo Island, Jeju (33.56°N, 127.02°E), a total of 22 barnacles were found to attach to one L. semifasciata caught. We identified these barnacles as Conchoderma virgatum based on their morphological characteristics such as distinctive feature of the capitulum and peduncle, the number of capitulum with reduced 5 plates, and the number of 2 scutum in Y-shape. There are a total of two types of barnacles (C. virgatum and Platylepas ophiophilus) that have been reported to attach to L. semifasciata in the world. Attached barnacles, including the C. virgatum, may restrict the behavior of sea kraits, cause dysecdysis, or cause the secondary infection through epithelial tissue damage. Therefore, further study on the relationship between barnacles and marine reptiles might be needed.