Online qualitative focus groups are a method which has been increasingly used, especially since the beginning of the Covid-19 pandemic, including in research with young people. Studies have reflected upon the challenges of conducting online qualitative research with young people, often drawing on experiences from the pandemic’s earlier stages. This article reflects upon the challenges faced, and choices made, when conducting online focus groups with 80 young people aged 14–18 to study their democratic engagement during the later 2021 wave of the pandemic. It highlights specific issues around the method’s effectiveness in engaging young people who face different kinds of marginalisation from democratic processes. While online modes of delivery were positive for engaging some, including groups of geographically dispersed young people, they exacerbated existing inequalities for others: young people from socioeconomically disadvantaged backgrounds, from remote or rural areas, and those with certain disabilities. Such inequalities in research participation can lead to variation in data quality, and therefore in the types of knowledge produced. Using these insights we outline a range of methodological and research design considerations for researchers when choosing whether to conduct online focus group research with young people.