Ulleungdo harbours a unique ecosystem owing to its isolation from the mainland alongside its maritime climate. The island, formed via volcanic activity, is the largest island in the East Sea of Korea and retains a primeval forest. The ecosystems are being destroyed owing to increasing human activity on the island. Therefore, through the investigation of the insect fauna of Ulleungdo, we tried to provide information that can be the basis for understanding the island ecology of Ulleungdo. This survey was conducted four times between April and October in 2020 at Seonginbong. The findings of the survey regarding insect fauna at Seonginbong, Ulleungdo included 10 orders, 105 families, 216 genera and 212 species, of which 12 families, two subfamilies, 13 genera and 74 species were previously unrecorded. The data have been registered in the Global Biodiversity Information Facility (GBIF; www.GBIF.org).