The COVID-19 global pandemic had a major impact on older people's mental health and resulted in changes in alcohol use, with more older adults increasing than decreasing consumption levels among the general population. So far, no studies have focused on older people who were already experiencing problem alcohol use. This qualitative research is the first to provide a nuanced understanding of changes to drinking patterns among older adults engaged in alcohol treatment during the COVID-19 pandemic, and the implications of these for practice. We conducted 30 semi-structured interviews with people in alcohol treatment aged 55+ living in urban and rural areas across the UK. Data were analysed using thematic analysis. We found that changes in alcohol use varied depending on the social, economic and health impacts of the pandemic on older adults. Boredom, lack of adequate medical or emotional support, and key life changes experienced during the pandemic (such as bereavement or retirement) increased the risk of increased drinking. Moreover, some people in longer-term alcohol treatment were struggling to maintain abstinence due to lack of face-to-face peer support. For others, decreased drinking levels were a side-effect of lockdown policies and restrictions, such as alcohol-related hospitalisations, closure of social spaces or inability to source alcohol; these also supported those who decided to cut down on drinking shortly before the pandemic. Generally, older adults who developed home-based interests and self-care practices managed lockdown best, maintaining abstinence or lower risk drinking levels. Based on these results, we argue that multilevel interventions aimed at strengthening resilience are required to reduce drinking or maintain abstinence among older adults. Such interventions should address three domains: individual (coping strategies and mindset), social (support networks), and structural (access to resources). In preparation for supporting older alcohol users through prospective future pandemics, building digital literacy and inclusion are essential.