Instilling a collaborative approach can widen participation to a range of stakeholders, enabling the diffusion of sustainability and increasing local capacity to meet decarbonisation targets to mitigate against climate change.Dingle Peninsula 2030has emerged as an international case study of a collaborative regional sustainability project, whereby a wide range of initiatives, beyond the initial remit of the project, have emerged in the area. This holistic scale of action is required for effective climate action. Using the Sustainable Development Goals (SDGs) as a framing, the interrelated nature of climate action has been shown through this study. In setting out to undergo energy projects a wide range of new initiatives emerged as community members became engaged in the process. Initiatives have emerged related to energy, transport, agriculture, education, tourism and employment, in what we have coined the ‘diffusion of sustainability’.