Along with transportation development, climate change and socio-economic changes, invasive alien species (IAS) are causing a significant decline in biodiversity around the world. Internationally, policies for pre-invasion management of IAS are being emphasised to minimise damage from biological invasions. In South Korea, through the 2nd Alien Species Management Plan (2019–2023), IAS that are not yet present in the country but are likely to be introduced are designated as Alert Alien Species (AAS). In this study, the overall process of AAS designation is summarised and improvements to the current system are presented. To select AAS, an invasive alien species database (IASD) of 8,456 species was built by integrating the IAS lists from many countries. Amongst them, 1,534 species, included in IASD at genus, family and order level, were excluded and 3,298 species confirmed to have been introduced to South Korea were excluded from the AAS candidate species. After the creation and review of species profiles by experts, 150 species were finally designated as AAS in 2023. The AAS discovery process needs to reflect international trends of IAS and be continuously supplemented through policy research of other countries. In addition, the IAS management system in South Korea, in which various ministries play their own roles with sufficient data sharing, should be systematically linked from introduction to control of IAS.