 Castington has the capacity to accommodate 128 sentenced and unsentenced juveniles (aged 15–17), 40 trainees (aged 15–17), as well as 120 sentenced and 120 unsentenced young offenders (aged 18–21).The prison is divided into seven units, all of which are equipped with integral sanitation.The prison provides full-time education and vocational training geared towards GCSEs, GNVQs and City and Guilds qualifications for all inmates.