The Updated checklist of the ants in Belgium is a species checklist dataset published by Institute of Natural Sciences. It contains information on 100+ ant species occurring in Belgium, detected between 1833 and 2023. Here it is published as a standardized Darwin Core Archive and includes for each species: the scientific name, kingdom, and stable taxon identifier (in the taxon core), the presence in Flanders, Wallonia and the Brussels Capital Region, the year of the first introduction (first collection) and last assessment/observation in Belgium (given as a year range), as well as the degree of establishment and the pathway(s) of introduction (in the distribution extension), coarse habitat information (in the species profile extension), and the native range(s) (in the description extension). Issues with the dataset can be reported at https://github.com/trias-project/belgian-formicidae-checklist. We have released this dataset to the public domain under a Creative Commons Zero waiver. We would appreciate it if you follow the INBO norms for data use (https://www.inbo.be/en/norms-data-use) when using the data. If you have any questions regarding this dataset, don’t hesitate to contact us via the contact information provided in the metadata. This dataset was published as open data for the TrIAS project (Tracking Invasive Alien Species http://trias-project.be, Vanderhoeven et al. 2017), with technical support provided by the Research Institute for Nature and Forest (INBO). It is selected as one of the authoritative sources for the compilation of a unified and reproducible checklist of alien species in Belgium.