Objective Feasibility test a co-developed intervention based on Acceptance and Commitment Therapy to support psychological adjustment post-stroke, delivered by a workforce with community in-reach. Design Observational feasibility study utilising patient, carer, public involvement. Setting Online. UK. Participants Stroke survivors with self-reported psychological distress 4 + months post-stroke. Interventions The co-developed Wellbeing After Stroke (WAterS) intervention includes: 9-weekly, structured, online, group sessions for stroke survivors, delivered via a training programme to upskill staff without Acceptance and Commitment Therapy experience, under Clinical Psychology supervision. Main measures Feasibility of recruitment and retention; data quality from candidate measures; safety. Clinical and demographic information at baseline; patient-reported outcome measures (PROMs) via online surveys (baseline, pre- and post-intervention, 3 and 6 months after intervention end) including Mood (hospital anxiety and depression scale (HADS)), Wellbeing (ONS4), Health-Related Quality of Life (EQ5D5L), Psychological Flexibility (AAQ-ABI) and Values-Based Living (VQ). Results We trained eight staff and recruited 17 stroke survivors with mild-to-moderate cognitive and communication difficulties. 12/17 (71%) joined three intervention groups with 98% attendance and no related adverse events. PROMS data were well-completed. The HADS is a possible future primary outcome (self-reported depression lower on average by 1.3 points: 8.5 pre-group to 7.1 at 3-month follow-up; 95% CI 0.4 to 3.2). Conclusion The WAterS intervention warrants further research evaluation. Staff can be trained and upskilled to deliver. It appears safe and feasible to deliver online to groups, and study recruitment and data collection are feasible. Funding has been secured to further develop the intervention, considering implementation and health equality.