This chapter explores varied transitions faced by athletes and the potential psychological challenges of these. It discusses theoretical models and empirical research on within-career transitions, with a case study used to contextualise the potential challenges athletes may face and the potential ways to manage the process. Dan is an 18-year-old rugby player who has just signed his first professional contract with a team that competes in the Premiership. The team which he plays for is very supportive of young players moving up from the youth team to first team. Transitions can be classified as normative transitions, which are those which are predictable and anticipated and non-normative transitions, which are those which are unexpected. Typically athletes transition to the development stage at the age of 12 or 13; this is the phase where athletes engage in an intensive level of training and competition with a specific focus on development for performance gains.