AIM: We aimed to compare characteristics and clinical presentation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody positive or negative children attending a specialist outpatient clinic for suspected paediatric long COVID. METHODS: A cross-sectional study was conducted of 113 children and adolescents enrolled between 1 December 2020 to 14 September 2021 in a multidisciplinary programme. Clinical and epidemiological data were collected with standardised interviews and laboratory tests including SARS-CoV-2 spike antibody measurement. RESULTS: A serological link to SARS-CoV-2 infection was found in 52%. Most patients (94.7%) reported several symptoms. Fatigue, post-exertional malaise, dizziness, nausea, headache, and concentration difficulties were the most common. Seronegative children had a higher number of individual symptoms. School absence and drop-out from leisure activities was substantial in both groups with higher numbers for the seronegative group. Self-reported health was low in both groups. CONCLUSION: Children attending a specialist paediatric long COVID clinic experienced multiple symptoms and poor self-reported health. The symptomatology was similar regardless of serological status, implying multifactorial causes. A multidisciplinary assessment of this cohort was essential considering the broad spectrum of symptoms displayed and their substantial impact on everyday functioning.