This repository contains the posters presented during the Open Science Day of the faculty of Geosciences at Utrecht University. The collection showcases the best practices, tools, and initiatives related to Open Science, FAIR data, research data management, reproducibility, and open scholarship across disciplines. The posters are published to increase visibility, accessibility, and reusability of the presented work, and to support knowledge sharing within and beyond the university. Each poster is accompanied by descriptive metadata and, where applicable, supplementary information to facilitate understanding and reuse.