Background Palliative care staff can experience stress, distress and burnout (Powell, Froggatt, Giga. BMJ Support Palliat Care. 2020;10(1):79–90; Smith, Vasileiou, Kagee. S African J Psychol. 2020;50(3):425–37; Dijxhoorn, Brom, van der Linden et al. Palliat Med. 2021;35(1):6–26). ACT is a mindfulness-based behavioural therapy aimed at improving wellbeing and promoting values-based living (Hayes. Behavior Ther. 2004;35(4):639–65), with emerging evidence of its effectiveness in palliative care. In autumn 2021, 23 palliative care staff completed an 8-week ACT based online programme which was acceptable to staff and feasible to implement (Finucane, Hulbert-Williams, Swash, et al. Palliat Med. 2023;37(2):244–56). A follow-up booster intervention was delivered in autumn 2022 to support sustainability of impacts of the original intervention over time.

Aims To explore the sustainability of outcomes from the original online ACT intervention one year on; to explore the barriers and facilitators to sustaining practice over time; to examine the acceptability and feasibility of a booster intervention; and to identify the implications for future implementation and evaluation.

Methods A booster intervention consisting of one short video and worksheet; followed by one online facilitated ACT workshop was offered to all 23 participants who completed the original intervention. Questionnaire data was sought at baseline and post-booster intervention; and semi-structured interviews were conducted. Qualitative data analyses were guided by framework analysis. Quantitative data was analysed descriptively.

Results Seven participants were recruited (32% of those completing the original intervention). Six attended the online session (86% of those recruited). 5 completed baseline questionnaire, only 1 completed the follow-up questionnaire. Qualitative findings indicated perceived benefits to participants in the year after the original programme. However, staff experienced challenges to embedding regular practice due to lack of time and expressed the need for regular facilitated check-ins and reminders to sustain practice over time.

Conclusions Online ACT for palliative care staff wellbeing is acceptable to staff and feasible to implement in the short term. However, for longer-term impacts, wellbeing promotion needs to be prioritised, facilitated, and embedded within palliative care teams. A greater focus on sustainability is needed during intervention development; and longer-term outcomes need to be prioritised for evaluation.