Due to the growing popularity of wireless communication as mobile communications reach a mass market; network operators are facing decreasing voice Average Revenue Per User (APPU). New revenue generating network services are required to slow or turn around this trend and operators are interested in data services such as Wireless Internet access and Mobile Commerce as a means to this end. This research examines the successful business models and strategies of leading operators in the mobile service market. The “case study” approach is focused on the Japanese market. Japan is at the cutting edge of the commercialization of wireless data service, and maintains the leading global market position. This paper consists of a global market development analysis, documenting Japan’s preeminence and justifying its selection for special study. The business model of Japanese wireless Internet operators is then described, in terms of its structure and critical success factors, based on comparative analysis of case studies, with particular reference to the “Co-opetitive” relationship between operators. Conclusions based on a consolidation of case analyses, can be summarized as recommendations for fostering “Co-opetition” by creating an environment favoring general expansion of the wireless network industry, and creation of a value system, fostering competition between operators. It is hoped these ideas will help innovation by Taiwanese network operators.