IntroductionPatients being discharged from inpatient mental wards often describe safety risks in terms of inadequate information sharing and involvement in discharge decisions. Through stakeholder engagement, we co-designed, developed and adapted two versions of a care bundle intervention, the SAFER Mental Health care bundle for adult and youth inpatient mental health settings (SAFER-MH and SAFER-YMH, respectively), that look to address these concerns through the introduction of new or improved processes of care.Methods and analysisTwo uncontrolled before-and-after feasibility studies, where all participants will receive the intervention. We will examine the feasibility and acceptability of the SAFER-MH in inpatient mental health settings in patients aged 18 years or older who are being discharged and the feasibility and acceptability of the SAFER-YMH intervention in inpatient mental health settings in patients aged between 14 and 18 years who are being discharged. The baseline period and intervention periods are both 6 weeks. SAFER-MH will be implemented in three wards and SAFER-YMH in one or two wards, ideally across different trusts within England. We will use quantitative (eg, questionnaires, completion forms) and qualitative (eg, interviews, process evaluation) methods to assess the acceptability and feasibility of the two versions of the intervention. The findings will inform whether a main effectiveness trial is feasible and, if so, how it should be designed, and how many patients/wards should be included.Ethics and disseminationEthical approval was obtained from the National Health Service Cornwall and Plymouth Research Ethics Committee and Surrey Research Ethics Committee (reference: 22/SW/0096 and 22/LO/0404). Research findings will be disseminated with participating sites and shared in various ways to engage different audiences. We will present findings at international and national conferences, and publish in open-access, peer-reviewed journals.