Recently domestic mobile carriers have been engaged in heated battles for survival as the market is now rapidly approaching its maturity phase. and the launch of 3G service combined with the introduction of mobile number portability is dramatically reshaping the market landscape. The mobile carriers may have to create and maintain their competitive advantage based on their core capabilities and differentiated strategies. which will lead continuous survival and profits of the firm. This paper investigated competitiveness factors among mobile carriers. and analyzed the relationships of firm capabilities. competitive strategies and competitive advantage. We found that core capabilities and competitive strategies affecting competitive advantage are different from each carrier. Finally. we discussed strategic implications for carriers to increase their competitiveness.