This dataset provides supplementary material accompanying a scientific article describing the SAIS harmonisation workflow for multi-national IACS data. It includes a GeoPackage with limited and anonymised samples of reference parcels, agricultural areas, and agricultural parcels from several EU Member States (AT, ES, FR, NL), as well as simplified SQL excerpts of selected production and control tables. The material is intended to support methodological inspection and parallel technical review and is not designed for operational use or statistical analysis. The deposit also includes the core SQL ingestion function used in the SAIS workflow, provided for methodological inspection rather than direct reuse as a standalone software component.