This volume constitutes the revised selected papers presented at the Workshops of the 41st International Conference on High Performance Computing, ISC High Performance 2026, which took place in Hamburg, Germany, during June 2026.The 71 full papers plus 5 state-of-the art research papers included in these proceedings were carefully reviewed and selected from 101 submissions. The papers were organized according to the following workshops:

Part I: 6th Workshop on Compiler-assisted Correctness Checking and Performance Optimization for HPC (C3PO’26); 6th Workshop on Communication, I/O, and Storage at Scale on Next-Generation Platforms- Scalable Infrastructures; Seventh Workshop on Interactive and Urgent High-Performance Computing (WIUHPC); HPC on Heterogeneous Hardware (H3),AI on HPC: Performance Engineering, Challenges and Opportunities, and The Second International Workshop on Foundational Large Language Models Advances for HPC (LLM4HPC).

Part II: International Workshop on RISC-V for HPC at ISC; Second International Workshop on Energy Efficiency with Sustainable Performance: Techniques, Tools, and Best Practices (EESP);10th International Workshop on In Situ Visualization (WOIV’26); 7th ISC HPC International Workshop on “Monitoring, Observability and Operational Data Analytics”’ (MODA26);12th Annual High Performance Containers Workshop (HPCW26) and Workshop Summary and State-of-the-Art Papers.