Background Living and environmental conditions in rural Bangladesh expose children to drowning. The Anchal programme protects children through crèche-based supervision in an enclosed space run by locally recruited carers. It is unclear under what conditions the programme best operates to maximise protection. We conducted a process evaluation of Anchal to determine enabling factors and challenges to implementation.

Methods Quantitative programme data were analysed to calculate metrics including child participation and fidelity of implementation to defined processes. Qualitative data collection with programme participants and implementers provided insights into barriers and enablers of implementation. Analysis was guided by the UK Medical Research Council’s process evaluation framework.

Results Anchal operated 400 centres with an average of 22.2 children enrolled, as per target. However, daily attendance averaged lower than the 80% target. Children aged 1–2 years old, who are most at risk of drowning, were least likely to enrol and attend regularly due to low engagement with activities and parental concerns for safety. Greater distances and lower educational attainment in some regions reduced attendance and increased carer attrition.

Conclusions The Anchal programme met most programme delivery targets. However, programme success could be improved through increasing supervision, providing communication training for implementing staff, designing programmes for children aged 1–2 years old, encouraging community ownership and providing child pick-up services. These contextual solutions can be adapted to similar programmes operating through grassroots-level engagement and recruitment of community health workers, to maximise their effectiveness and sustainability.