A key focus of youth sport research is to understand how young people can have positive developmental experiences in sport settings. During middle childhood and early adolescence, many children choose to progress from recreational sports to competitive pathways. However, there is limited research that has examined how children's transitional experiences in sport impact, and are impacted by, their psychosocial development. Therefore, the aim of this research was to explore how children and parents navigate the transition from recreational to competitive sports alongside key psychosocial developmental experiences. Using a mixed-methods longitudinal design, 7 parent-child dyads completed semi-structured interviews and measures of social competence (Rydell, 1997) and self-perceptions (Harter, 1999) at three timepoints across one year (2020 – 2021). Qualitative data were analysed using thematic analysis (Braun et al., 2019) and considered alongside changes in quantitative measures. The results illustrated how parents and children navigate changes in their relationship including the children's growing independence; how parents and children manage various types of transitions including successful, unsuccessful, and non-transitions; and how children develop psychosocial competencies through key transitional experiences in sport. Results also illustrated the impact of the COVID-19 Pandemic, which created additional opportunities and challenges both in and beyond sport. In conclusion, the transition to competitive sport present children with key experiences that can impact their psychosocial development in both positive and negative ways. Parents can support children during their transition to competitive sport by helping children to identify competencies in multiple domains.