["Nations and Nationalism, EarlyView. ", "\nABSTRACT\nSince 1992, the proportion of citizens in Taiwan who identify exclusively as Taiwanese, rather than holding dual identities, has steadily risen. Although short‐term fluctuations in national identification have attracted scholarly attention, there has been little systematic investigation into the magnitude of these shifts or the factors that may drive them. This study draws on daily national survey data to examine how a high‐profile international baseball tournament contributed to changes in Taiwanese national identification. Our research contributes to the literature on ecstatic nationalism, which emphasises emotionally charged and collective expressions of national identity in response to high‐profile national events. The findings reaffirm baseball's longstanding cultural role in shaping nationalist sentiment in Taiwan and demonstrate that its effects vary by party affiliation. In particular, the results underscore the contested and dynamic nature of national identity and highlight the need for further research into the mechanisms driving these fluctuations.\n"]