This paper presents a Circular Digital Twin (DT) applied to climate-smart soils in a UNESCO Global Geopark, oriented towards the sustainable management of water use and organic matter, with a focus on climate change mitigation through carbon sequestration. Based on the Design Science Research approach, the study follows an iterative design and development cycle, which includes an ex-ante evaluation of technical and human risks. The Circular DT’s architecture integrates sensors with real-time data analysis, using the Spiral Knowledge Management and Strong Structuration Theory to propose design principles. The results indicate that the Circular DT can promote efficient resource management in the agricultural context and contributes to closing the loop in the food supply chain, encouraging community composting and the use of organic waste in the soil. It also facilitates adaptive and inclusive management of soils and natural resources, which aligns with the sustainability standards of UNESCO Geoparks and the GEOfood initiative. The main contribution is a replicable DT for smart soils that support sustainable agricultural practices in the circular economy. The design principles strengthen the body of knowledge on DTs applied to natural resources, with the potential to support the transition to regenerative agricultural systems.