AbstractSince there is fierce competition in the global high‐speed rail (HSR) market, pursuing sustainable development has become an essential task for HSR firms. However, competition on the international HSR projects shows prominent dynamic characteristics, which pose severe challenges to the sustainable development of HSR firms. Transient competitive advantage (TrCA) as a kind of advantage, that can be built quickly and abandoned rapidly, would guide HSR firms winning awards and survival in the dynamic competitive environment. To explore how HSR project bidders achieve their TrCA in the bidding process, this study conducted a multicases approach. We have collected the data by using the query‐based website crawler as well as focus group discussion. First, the main strategic activities were identified while their sources and roles were discussed in the context of TrCA theory. Then, a conceptual framework was developed to reveal the improvement of TrCA. To the best of our knowledge, this is the first work that proposes conceptual framework for TrCA improvement. Implications related to the findings are proposed to understand the formation and improvement of TrCA further. The results provide a comprehensive guidance for HSR project bid managers, market players, and future market entrants adopting main strategic activities.