The IRIDE Cyber Italy Coastal Digital Twin (DT#3) is an advanced Digital Twin designed to support decision-making in coastal management by integrating Earth Observation data, numerical models and artificial intelligence techniques. The project addresses critical coastal challenges such as erosion, flooding and water quality degradation, providing data-driven insights and predictive simulations to support policymakers, environmental agencies and researchers. The system will enable real-time scenario simulations and risk assessments through a web-based interface, allowing stakeholders to explore different mitigation strategies and improve coastal resilience. Developed as part of the IRIDE Cyber Italy initiative, this Digital Twin serves as a prototype for future expansions, with the potential to be applied to other coastal areas in Italy and beyond. By leveraging cutting-edge technology and high-resolution environmental data, the DT#3 aims to enhance sustainable coastal planning, infrastructure optimization and climate adaptation efforts.