This open access book constitutes the refereed proceedings of the Third International Workshop on Simulation Science, SimScience 2025, which took place in Clausthal-Zellerfeld, Germany, during May 7–9, 2025.

The 7 full papers included in this book were carefully reviewed and selected from 44 submissions. SimScience 2025 aimed to bring together researchers and practitioners from both industry and academia to report on the latest advances on simulation science. The workshop focused on both simulations and AI and their interaction.