This article reports outcomes from a 15-month (2018-19) study led by UCL on behalf of the Culture, Health and Wellbeing Alliance in partnership with three London museums of differing sizes with natural or local history collections. The study aimed to address mental health inequalities by diversifying volunteer populations through reforming recruitment procedures to overcome perceived barriers, and enriching training programmes to improve wellbeing. A mixed methods approach was used to assess wellbeing and mechanisms by which key benefits were derived, such as social interaction and forming connections. The article considers how increasing the diversity of volunteer training in museums can improve wellbeing, widen access and promote social inclusion. Policy and practice implications are discussed in relation to embedding wellbeing training strategies into heritage organizations