The two-volume set LNCS constitutes the main proceedings of the 26th International Conference on Computational Science, ICCS 2026, which took place in Hamburg, Germany, during June 29 – July 1, 2026.The 59 full papers and 35 short papers presented in these proceedings were carefully reviewed and selected from 177 submissions. The conference is focusing on recent developments in scalable scientific algorithms; advanced software tools; computational grids; advanced numerical methods; and novel application areas.The theme for 2026, "At the Forefront of Science through Computation and Data", highlighted the role of Computational Science in assisting multidisciplinary research.
