Local digital twins require existing interoperability tools and standards to integrate diverse urban data sources seamlessly. Fragmented data leads to inefficiencies, hindering the predictive capabilities crucial for urban planning. Without robust interoperability frameworks, digital twins become costly and isolated, impeding their potential for scalable and future-proof urban solutions. Cities should strategically adopt open standards and guidelines from interoperability organizations to establish effective local digital twins. By defining their digital twin requirements and systematically using frameworks like CityGML, SensorThings API, and others, cities enable consistent data understanding across systems, fostering scalable and reusable digital implementations. This unit explores key data interoperability efforts, including Minimal Interoperability Mechanisms, the INSPIRE Directive, DIN SPEC 91607:2024-11, and standards from the Open Geospatial Consortium. Students learn how these frameworks facilitate seamless data sharing and integration for digital twins, enhancing urban management and planning through consistent, cross-domain data utilization.