The Open-Earth-Monitor Global Workshop 2025 continues to stand as one of the flagship events for the open-source geospatial community in Europe. Under the title “Open EO data and open source software as a foundation for monitoring the European Green Deal”, this fourth edition will be hosted in Perugia, Italy, from 17 to 19 September 2025. Jointly organized by the OpenGeoHub Foundation, the Department of Civil and Environmental Engineering at the University of Perugia, and the National Research Council of Italy (CNR), the workshop will gather European and global actors—spanning policy makers, researchers, business leaders, and civil society—to explore and advance open Earth Observation data and open‑source software solutions in support of the European Green Deal