Unsafe child faeces management can lead to adverse health and wellbeing outcomes for children. In Solomon Islands, diarrhoeal disease is a leading cause of under-5 mortality, though there is limited research into CFM practices and promotion of safe behaviours. The formative research applied a Behaviour-Centred Design framework to investigate the habits, motives and settings related to child faeces management in rural Solomon Islands villages. Data were collected through structured recall demonstrations by caregivers (n = 61), household infrastructure observations (n = 57), semi-structured interviews with caregivers (n = 121) and community leaders (n = 30), focus group discussions (n = 26), and three participatory activities with caregivers. The findings identified a range of CFM-related behaviours, some of which would be considered safe and some, such as outside defecation and disposal to a waterway, as unsafe. Convenience is important in shaping CFM practice and may help health benefits to be achieved without women bearing the cost of an increased work burden. Nurture and disgust may provide the basis for behaviour change communication in SI as they have elsewhere. Critically, the participation in and promotion of safe CFM by fathers in households should be promoted, and motivating such behaviours might be achieved through focus on nurture as a motive.