Background Long COVID is a newly recognised condition that also affects children and young people (CYP). However, little is known about how it impacts their daily lives and well-being from their own perspective. This study aimed to explore the lived experiences of CYP living with long COVID. Methods Swedish-speaking CYP who developed long COVID before the age of 18 years were invited to participate in semistructured interviews. Between February and September 2024, seven CYP (four girls and three boys) participated (mean interview duration=51 min). Data were analysed using reflexive thematic analysis to identify codes and then themes with related subthemes. Results Two main themes were generated. The first main theme ‘I am stumbling in the dark: Living with unpredictability and limitations’ covers how CYP were affected by the consequences of long COVID. The subtheme ‘How do I live and function now? ’ illustrates how the CYP tried to navigate the disabling and yet fluctuating symptoms, and the subtheme ‘Who am I now?’ represents the identity-related consequences. The second main theme ‘Navigating responses from others to find support’ illustrates how others have responded to their symptoms and how these responses were perceived by the CYP. The subthemes ‘Stop being sceptical!’, ‘Just try to help me!’ and ‘Accept and validate me!’ illustrate interactions perceived as invalidating or disrespectful, what has been experienced as helpful or unhelpful and the kinds of support adolescents have valued. Conclusions Long COVID negatively impacted the CYP’s lives, affecting their relationships, education, leisure activities and sense of identity. Dismissive and sceptical attitudes from professionals and peers substantially increased the burden, whereas encountering acceptance and knowledgeable professionals facilitated coping with long COVID.