ObjectivesEvidence shows paediatric critical care (PCC) nurses display high rates of burnout, moral distress, symptoms associated with post‐traumatic stress disorder (PTSD) and poor well‐being. The COVID‐19 pandemic magnified these pressures producing extremely challenging working conditions. The objective was to understand PCC nurses' lived experience of working during COVID‐19 to determine the impact it had on their well‐being.DesignA qualitative design was used with individual, semi‐structured online interviews analysed using thematic analysis.ResultsTen nurses from six PCC units in England participated. Five themes were generated: (i) Challenges of working in Personal Protective Equipment (PPE), (ii) Adapting to redeployment to adult intensive care, (iii) Changes to staff working relationships, (iv) Being unable to attain work‐life balance and (v) Unprocessed traumatic experiences of working in COVID‐19. It was clear COVID‐19 presented novel challenges to PCC nurses' well‐being. With those came enforced changes in practice; some were temporary, for example use of PPE and redeployment, but others provided insight into the prerequisites for good staff well‐being, for example strong professional relationships, work–life balance and managing one's psychological health.ConclusionsFindings show authentic connections between peers, verbal and non‐verbal communication and a sense of belonging were crucial to nurses' well‐being. A dent in PCC nurses' perceived competence significantly affected their well‐being. Finally, staff need a psychologically safe space to process distress and trauma experienced during COVID‐19. Future research needs to test evidence‐based, theoretically‐informed well‐being interventions to improve and maintain PCC nurses' well‐being.