COVID-19 may have substantial impact on the mental health at a population level, but also has the potential to significantly affect those with pre-existing mental health difficulties such as eating disorders. This qualitative study explores the impact of COVID-19 and associated public health measures on adults with eating disorders within the UK. We conducted 10 in depth interviews with adults (24-38 years) with a self-reported eating disorder during lockdown. Data were analysed using an inductive thematic analysis approach. We identified core themes related to social restrictions (social isolation, changes in accountability to others, and increased responsibility for self and others), functional restrictions (lack of routine and structure, a need to intentionally plan activity, a desire for secrecy particularly around food shopping) and restrictions in access to mental health services. Overall, the impact of the lockdown was experienced as a catalyst for either increased disordered eating behaviours or for a drive for recovery, depending on individual circumstances going into these restrictions. This study is the first in depth interview approach with adults with mixed eating disorder presentations in the UK during COVID-19. Findings have important implications for post lockdown intervention care and practice.