This book constitutes the refereed post-conference proceedings of the 12th International Conference on Wireless and Satellite Services, WiSATS 2021, held in Nanjing, China, in September 2020. Due to COVID-19 pandemic the conference was held virtually.The 79 full papers were carefully reviewed and selected from 140 submissions. The conference’s central theme is the means of using the wireless and satellite services directly to the user for personal communications, multimedia and location identification. The services enabled by WiSATS not only cover the requirements of an ordinary citizen but also provide personal and public services for global coverage communications as the applications of internet of things.