BACKGROUND: Transition to Specialty Practice Programs was introduced to facilitate the transition of nurses to specialty practice, and is recognised as preparatory for emergency nurses. Emergency nursing Transition to Specialty Practice Programs and their characteristics have developed locally in response to unit needs. OBJECTIVE: The aim of this study was to examine the characteristics of emergency nursing Transition to Specialty Practice Programs in Australia, and identify which characteristics were associated with improved professional development outcomes. METHODS: An explanatory sequential design was used. Data were collected via online surveys and interviews of emergency Nurse Managers and Nurse Educators. Transition to Specialty Practice Program characteristics were compared using Mann Whitney U and Chi-Square tests. Content analysis was used to analyse qualitative data. RESULTS: Survey data were collected from 118 emergency departments, and 13 interviews were conducted. Transition to Specialty Practice Programs were offered in most emergency departments (n=80, 72.1%), with one or two intakes per year. Transition to Specialty Practice Program characteristics varied; duration ranged from 5-12months, clinical preparation time ranged from 7-22days, and the number of study days provided ranged from 2-6. When Transition to Specialty Practice Programs of 6 and 12months duration were compared, there was no difference in the content covered. Emergency departments with 12month Transition to Specialty Practice Programs had lower percentages of Clinical Specialists (9% vs 18%, p=0.03) and postgraduate qualified nurses (30.5% vs 43.8%, p=0.09). CONCLUSION: The target participants, duration and clinical preparation of Transition to Specialty Practice Programs participants varied, impeding workforce mobility and articulation to postgraduate study and there were no professional development advantages from longer programs. There is an urgent need for a nationally consistent, evidence-based and fiscally responsible approach to Transition to Specialty Practice Programs.