Worldwide, the COVID-19 pandemic represented a health emergency for prisons. This study sought to understand the meanings and experiences through the narratives of prisoners and family members affected by the COVID-19 pandemic in the context of a maximum-security state penitentiary complex in southern Brazil. For this purpose, a qualitative study was developed based on the methodological framework of constructivist grounded theory. Data were collected between February and August 2022 through individual in-depth interviews and field notes. The sample consisted of 41 participants: 28 male prisoners, and 13 family members. Guided by the Charmaz method of grounded theory analysis, the study afforded the core category “Feeling trapped in prison during the COVID-19 pandemic” with three interrelated phases: “Triggering”, “Escalating”, and “Readjustment”. The “Triggering” phase refers to COVID-19-related elements or events that triggered certain reactions, processes, or changes in prison. During the “Escalating” phase, participants became overwhelmed by the suffering caused by incarceration and the pandemic crisis. The “Readjustment” phase involved adapting, reorienting, or reformulating previous approaches or strategies for dealing with a specific situation. Prisons faced complex challenges during the pandemic and were forced to prioritize protecting public health. However, the measures adopted must be carefully evaluated, ensuring their needs and that they are based on scientific evidence. The punitive approach can undermine inmate trust in prison authorities, making it difficult to report symptoms and adhere to preventive measures.