The CEOS CalVal portal serves as the main forum for exchange and information sharing for the CEOS Working Group on Calibration and Validation. In additions, it provides access to agreed good practices and Cal/Val protocols to the wider Earth Observation community within CEOS and beyond. It connects users to reference data and networks and provides reliable, up-to-date and user friendly information useful for Cal/Val tasks, facilitating data interoperability and performance assessment through an operational CEOS coordinated & internationally harmonised Cal/Val infrastructure consistent with QA4EO principles.