"Contrats de Rivière IAS surveillance : monitoring of aquatic and riparian invasive alien species in Wallonia, 2023" is a presence/absence dataset focusing on invasive alien aquatic plants and crayfish collected from the field all over Wallonia (Southern Belgium) since spring 2023. Data are derived from the monitoring of a set of priority ponds and river stretches where observations of IAS were reported in the past to allow site prioritization for management purposes. Data compilation, cleaning and validation were performed by the Département de l’Etude du Milieu Naturel et Agricole (SPW ARNE / DEMNA).