An updated list is presented of the alien species in the establishment or spread invasion stage in inland waters at the Iberian Peninsula. The list is based on a systematic assessment of information in collaboration with a wide expert team from Spain and Portugal. This updated list is an important tool supporting the implementation of the IAS Regulation and provides a factual basis for the review of its application. Ultimately, the information included can be used for monitoring the achievement of the target of the EU Biodiversity Strategy to 2030 for combatting IAS, but also for the implementation of other EU policies with requirements on alien species, such as the Birds and Habitats Directives, and the Marine Strategy and Water Framework Directives.