This book constitutes the refereed proceedings of the 7th International Symposium on Ubiquitous Networking, UNet 2021, held in May 2021. Due to COVID-19 pandemic the conference was held virtually. The 16 revised full papers presented together with 6 invited papers and 3 special sessions were carefully reviewed and selected from 38 submissions. The papers are organized in topical sections: ubiquitous communication technologies and networking; tactile internet and internet of things; mobile edge networking and fog-cloud computing; artificial intelligence-driven communications; and data engineering, cyber security and pervasive services.