This open access book constitutes the revised selected papers of the 56th International Simulation and Gaming Association Conference, ISAGA 2025, held in Stuttgart, Germany, during July 15–18, 2025.The 23 full papers and 1 short paper presented in this volume were carefully reviewed and selected from 51 submissions. They are grouped into the following topics: Designing Futures: Innovation in Game Design and Development; Learning and Evaluation in Simulation-Based Environments; Sustainability, Climate, and Urban Resilience; Immersion and Intercultural Perspectives.