Research has shown the importance of prospective thinking in the understanding of individual behaviour across different contexts. However, there has not been extensive attention paid to individuals’ future time perspective (FTP) in non-normative contexts, such as prison, especially using qualitative research methods. In this study, we qualitatively analyse the FTP of 16 Portuguese male prisoners, ranging in age from 24 to 51 years (M = 35, SD = 8 (idem)) and serving sentences from one to 25 years (M = 8.6, SD = 7.3). Through content analysis of data obtained in semi-structured interviews, four main categories emerged: life prior to prison, adaptation to prison, activities in prison, and perspectives concerning the future. Considering the primary features of FTP (content, extension, valence), we determined that prisoners develop FTP in different life domains. However, the extension and emotional valence of their FTP were influenced by the sentence time and perceived social support. The results are discussed regarding the importance of counselling and of the construction of future plans in the context of prison as relevant factors for individual adaptability.