GeomodelatorGUI is a graphical user interface for Geomodelator, an open-source Python-based software that converts static geological models into simulation grids for subsurface assessments. The GUI, built on a modular client-server architecture, enables efficient modeling on low-memory systems and direct visualization of results without requiring third-party software.GeomodelatorGUI is based on python, streamlit and pyvista to use the free GEOMODELATOR to setup 3d geolocial models for the simulator framework TRANSPORTSE.