On August 21, 2023, the National Institute of Ecology reported the sighting of an invasive slug resembling Limax maximus Linnaeus, 1758. near Bambat Tree Frog Park, Suwon-si, Korea. This slug is known for its aggressiveness. Specimens were collected around the park and from nearby farms. Through barcoding analysis and sequence comparison, it was identified as L. maximus, confirming its presence in Republic of Korea, alongside two previously identified Limax species, Limax flavus Linnaeus, 1758 and Lehmannia marginatus O. F. Müller, 1774. This study represents the first documented report of L. maximus in the country.