Post-COVID syndrome is widely recognised in children and young people (CYP), where one or more persistent physical symptoms are present 12 weeks after the initial infection that cannot be explained by an alternative cause. We aimed to assess whether an intervention based on narrative therapy and breathing pattern retraining, co-designed with CYP with PCS (12–18 years) was feasible and acceptable within an NHS service. Participants were randomised to standard clinical care or intervention plus standard clinical care. The primary aim was to assess acceptability and feasibility within the study cohort. Intervention effects were evaluated using the Strengths and Difficulties Questionnaire (SDQ) Impact Score,with additional secondary outcomes included the Nijmegen questionnaire, Chandler Fatigue, and EQ-5D-Y, wellness rating, pulmonary function, and exercise testing. Thirty-two CYP were randomised to standard treatment ( n = 15) or intervention ( n = 17), mean age of 15 years, and 11 (34%) male. Twenty-seven (84%) were diagnosed with breathing pattern disorders. Four intervention groups were offered over 6 months. 14/17 completed the session. Qualitative feedback was positive. There was no statistically significant improvement in the SDQ over time or between groups. Nearly all secondary outcome measures showed statistically significant improvement over time (< 0.001) but not between groups. Conclusions : The intervention was acceptable and feasible to run in an NHS clinic setting for CYP with post-COVID syndrome. Significant improvements seen with time in secondary outcome measures in both groups indicate that post-COVID symptoms improve with time independent of the intervention. What is known – What is new: • Post-COVID syndrome (PCS) affects up to 66.5% of children and young people (CYP) with common persistent or fluctuating symptoms of fatigue, headaches, anxiety, brain fog, breathlessness, and post-exertional malaise and symptom exacerbation. • Few interventions have sought to address both the physical and mental health impact of PCS in adults and the evidence remains limited for CYP. • This novel psychology/physiotherapy co-designed intervention is acceptable and feasible in an NHS clinic setting. • We identified that breathing pattern disorders are common and a predominant cause of breathlessness in teenagers with PCS.