As a crucial link between theoretical preparation and practical teaching in higher education, pre-service teachers' emotional management has garnered increasing attention, particularly regarding emotional intelligence (EI) and emotion regulation (ER). However, most existing research has been cross-sectional, lacking a longitudinal perspective on how these emotional capacities evolve during the practicum. Addressing this gap, the present study investigates the developmental trajectories of, and interrelations between, EI and ER among pre-service teachers using a longitudinal design. Participants included 225 fourth-year undergraduates from nine majors in a teacher education programme at a normal university in China. Latent growth curve modelling revealed that both EI and ER followed linear growth trends, with significant individual differences in EI but not ER. Cross-lagged panel analysis indicated that while EI remained relatively stable, ER development was more dynamic. Importantly, EI at mid-practicum significantly predicted ER at the end. These findings underscore the stability of EI, the variability of ER, and the predictive influence of EI on ER, highlighting the importance of embedding emotional competence training and emotional support systems within the practicum experience.