This book constitutes the refereed proceedings of the 6th International Conference on Computing Science, Communication and Security, COMS2 2025, held at Ganpat University, Mehsana, Gujarat, India, during September 12–13, 2025. The 27 full papers and 1 short paper presented in this volume were carefully reviewed and selected from 238 submissions. They are organized into the following topical sections: Network and Communication Security; and Computing Science.