Public Health Scotland used Scottish national contact tracing data to estimate the European football championship (EURO 2020) contributions to a third wave of SARS-CoV-2 infections. From 11 June to 7 July 2021, 2,632 (4%) of 63,874 SARS-CoV-2 cases self-reported attending a EURO 2020 event; 90% were male, of whom 73% were 20-39-year-olds. Most cases attended unofficial gatherings and averaged more contacts than the general population. Targeted guidance on celebrating safely in closed spaces is key.