Faced with the challenge of global change, research on social innovations is multiplying in Europe and North America. In the gaps left by institutions, social innovations highlight the capacity of individuals and groups to develop alternative projects and practices that promote socio-ecological transitions toward sustainability, whether in terms of food, energy, economics or ecology. In some territories, social innovation networks are developing. In this contribution, we suppose that the weaving of links between holders of alternative projects and their networking can considerably foster the transformation of territories toward sustainability. Relying on the results of a vast study on social innovations in mountain territories in the Auvergne-Rhône Alpes region, carried out within the Labex research programme "Innovations and transitions in mountain territories" of the University of Grenoble Alpes (2018-2024), we will discuss this hypothesis. We will give particular insights into the case of the central part of the Bauges massif, in the French Alps, while comparing it to the situation of other territories we have studied. This territory, made up of 14 municipalities, is not known for its strong dynamics of alternative activities or transition. However, a real dynamic of social innovations has gradually been emerging. How has this territory, with its strong identity but far from institutional centres, become a space for the development of social innovations? How are these innovations able to transform the territorial trajectory towards sustainability? To answer these questions, we use a conceptual framework stemming from social geography, sustainability transitions studies and territorial development theories we have been elaborating on behalf of this research programme. It allows for analyzing territorialized network dynamics of social innovations and territorial transformations (through the inventory of initiatives, the geo-history of the territory, the types and functions of the networks) as well as a transdisciplinary approach (participative workshops between researchers and actors to identify the issues) are mobilised. The first findings allow us to say that the fabric of social innovations in the Bauges, although still not very well developed, has already achieved a high level of visibility, through the strong networking of its actors. We will show that one of the key issues for a real transformation lies in overcoming the divisions between the categories of actors (former residents, actors carrying alternative initiatives, etc.).