Community and voluntary organisations harness and develop network ties and resources, volunteerism and civic participation. Organisations contribute to society’s social capital stock and play a role in maintaining social cohesion, supporting civil society and generating social renewal. National community and voluntary organisations can operate at a macro (national), meso (regional) and micro (local) level. In doing so, different forms and mixtures of bonding, bridging and linking social capital can be created at these various levels. This research examines different forms of social capital within the various levels of a national community and voluntary organisation and explores how this social capital is mobilised in achieving organisational aims and objectives. This research utilised a case study framework, centred on the structure, activities and operation of the Federation of Active Retirement Associations, whose aims are to address issues relating to isolation and loneliness. This research employed a triangulated-methodology, which included both quantitative and qualitative data gathered through nine semi-structured interviews; observations at both a regional and national level; and 31 self-administered survey questionnaires, together with a secondary quantitative analysis of the organisation’s archives. This research demonstrates that the Federation has tapped into a changing societal profile by establishing a network to address issues important to older people, through a process of active participation. The continued increase in membership affiliations, together with the changing profile of local associations to smaller, more close-knit and parish-based organisations, has enabled the development of large reservoirs of strong ties and mobilised bonded social capital at the local level. The research identifies the importance of meso (regional) structures, supported by development officers, in the development and mobilisation of the Federation’s social capital as a whole and bridging social capital in particular. However, this research provides evidence of a lack of mobilisation of the organisation’s reservoir of social capital at a national level, in achieving organisational goals such as supporting collective participative activity. By examining how the differing forms of social capital within this case study are mobilised, this research may assist practitioners within the community and voluntary sector in mobilising their own organisation’s social capital.