Although there have been different rehabilitation activities introduced by Tanzania Prison Services (TPS) since independence to reduce recidivism, the rate of recidivism has remained relatively high with the prevalence of reoffending and stigma on the part of ex-prisoners. Failure to effectively implement rehabilitation activities is said to be among the causes of an increase in recidivism by the ex-prisoners. With support from cognitive behavioural therapy, human capital theory, and labelling theory, this study aimed to explore the effects of rehabilitation activities on reducing recidivism in Tanzania by combining quantitative and qualitative analyses. Data were collected through surveys, interviews, discussions, and observations. Quantitative data were analysed through descriptive statistics and binary logistic regression, while qualitative data were analysed through content analysis. Findings revealed that informal rehabilitation activities were not able to reduce the reoffending behaviour of recidivists. The effective rehabilitation activities were those focused on life skills, psychosocial aspects, and educational programs. Problems such as curriculum design, financial constraints, infrastructure limitations, attendance problems, and varying literacy levels among prisoners pose obstacles to the effective rehabilitation of prisoners. Therefore, rehabilitation initiatives should focus on generating practical skills that contribute to the successful reintegration of prisoners into society. In addition, life skills, spiritual, psychological, and educational programs must be supported by authentic curricula and well-defined delivery modes. Prison management should also be sensitized to the importance of disciplinary science, aftercare services, and startup capital for enhancing reintegration, proper rehabilitation, and reducing recidivism among prisoners.