Problem: Lack of opportunity for breech training and clinical experience reduced professional confidence and expertise in supporting vaginal breech birth., Background: OptiBreech collaborative care is a care pathway for breech presentation at term that aims to enable improve safety through person-centred care and improved training opportunities for maternity professionals, within dedicated clinics and intrapartum support. In feasibility work, barriers and facilitators to team implementation were observed by team members., Aim: This study sought to describe factors affecting optimal future implementation and safety of OptiBreech care., Methods: Semi-structured interviews were conducted with staff members at 13 OptiBreech trial sites (17 midwives and 4 obstetricians, n=21), via video conferencing software. The Theoretical Domains Framework (TDF) was used to identify factors impacting team implementation. Themes identified in the TDF were refined in reflexive discussion and grouped into key facilitators, key barriers, and dynamic factors (which span both barriers and facilitators). The interviews were then coded, analysed, and interpreted according to the refined framework., Findings: The key facilitators were broadly categorised within skill development, beliefs about capabilities, and social support from the wider multidisciplinary team. Key barrier categories were resources, social obstacles, and fears about consequences. Dynamic factor categories were individual responsibility, training, and attending births., Conclusion: While some factors affecting implementation were specific to the individuals and cultures of certain Trusts, recommendations emerged from analysis that are more widely applicable across multiple settings. These should be considered going forward for future service implementation, and in the next stage of OptiBreech clinical trials., (Copyright © 2024. Published by Elsevier Ltd.)