This book constitutes the refereed proceedings of the 6th International Conference on Design, Operation and Evaluation of Mobile Communications, MOBILE 2025, held as part of the 27th International Conference, HCI International 2025, which was held in Gothenburg, Sweden, during June 22-27, 2025. The total of 1430 papers and 355 posters included in the HCII 2025 proceedings was carefully reviewed and selected from 7972 submissions. The MOBILE 2025 proceedings were organized in the following topical sections- Mobile Usability, Experience and Personalization; Mobile Health, Inclusivity and Well-Being; Mobile Security, Protection and Risk Assessment; and, Mobile Applications for Culture, and Social Engagement.