This volume LNCS constitutes the refereed proceedings of 31st European MPI Users' Group Meeting, EuroMPI 2024, held in Perth, WA, Australia, during September 25-27, 2024. The 8 full papers presented here were carefully reviewed and selected from 19 submissions. These papers have been categorized under the following topical sections: Compile-time Correctness checks and optimization; Limitations and Extensions for GPGPUs in MPI; Improvements for MPI and MPI Ecosystem.