This study is about the transition planning of young people with special educational needs (SEN) from secondary mainstream and special schools to post-secondary opportunities. Leaving secondary school is the first task related to the transition to adulthood and it has been identified as a particularly complex task for pupils with SEN. A systematic literature review was undertaken to start to develop a 'map of transition', a framework of positive transition practice. Interviews with key professionals, parents and teachers and pupil case studies were used to generate qualitative data. It was used to analyse transition practice in the real world of schools and the involvement of families, pupils and external services. This study was particularly concerned with understanding any barriers or gaps of transition work. Pupil annual reviews, including those adopting a person-centred format were thematically analysed in terms of their ability to address transition planning and future options. Results suggest similarities and differences in transition planning practices between mainstream and special schools. In both settings there was appreciable reliance on the Connexions Service. For pupils with SEN in mainstream schools transition planning could be conceptualised as 'invisible transition'. It was a not an explicit process, with experiences and access to services likely to be related to schools' perception of need, option pathways and whether or not pupils had a Statement of SEN. In special schools, transition planning was conceptualised as 'visible but blurred'. It centred on gaining external service involvement, with limited focus on transition-related education. In both mainstream and special schools there were difficulties with the compilation of distinct transition plans and their implementation.Tensions related to unclear roles and responsibilities, difficulties with access to external services and limited post-secondary opportunities were highlighted. This allowed revision and extension of the 'map of transition'. The study leads to suggested improvements to service delivery for young people by schools and other stakeholders.