This book constitutes the revised selected papers of the 18th EAI International Conference on Mobile Multimedia Communications, MobiMedia 2025, held in Lhasa, China, during August 15–17, 2025.The 26 full papers included in this book were carefully reviewed and selected from 70 submissions. They are organized in topical sections as follows: Algorithms, Architecture, Applications of 5G/6G; Flexible Architecture in AI-Enabled Software-Defined Networks; Wireless Body Area Network (WBAN); Computational Framework and Structure for Big Data. Localization, Positioning and Tracking Techniques; Heterogeneous Data Storage; Multimedia-Based Signal Processing; Mobile Crowdsensing; Real-Time Stream Data Mining; and AI for Communication.