These files are the two Supplementary Materials of the report 'Invasive Alien Species Horizon Scanning in support of implementation of Regulation 1143/2014 - Final Study Report', as produced by IUCN together with several scientific experts from Europe in 2025. An updated methodology was put together, consisting of gathering species lists from global horizon scanning exercises and additional databases. These lists were refined, after which a rapid assessment of a subset of some species was undertaken to evaluate their potential invasiveness, followed by consensus building to achieve a final list of prioritised species through an in-person workshop. Supplementary Material 1 refers to the lists of species that were excluded from the initial long list of candidate species due to: 1) a lack of robust distribution data and 2) their being considered widely spread in the EU, defined as occurring in three or more 50x50 km grid cells in the EU, based on GBIF data. Supplementary Material 2 includes 1) a list of 57 species that were deemed to present the highest threats to biodiversity in the EU in the next 10 years, 2) a list of 108 species that were deemed to also be of high risk to EU biodiversity and 3) the 457 remaining species that were put forward for scoring by the experts. This dataset represents a raw supplement to the original report. A tidy plain text file format will be made available for use in R or python linked to this dataset.