Seed movements are more than a manifestation of the struggle to increase farmers’ and gardeners’ access to seeds. In this article, we explore seed saving and sharing as networked practices for the maintenance of genetic diversity as well as for social innovation in a new type of seed exchange networks in Hungary, Austria, Spain, Switzerland, and the UK and the European Coordination of the Let’s Liberate Diversity network. We analyse our qualitative interview data using Transformative Social Innovation theory as a new perspective to link social movement and social innovation literature. We focus on the emergence, dynamics, and agency of seed exchange networks in Europe as innovative social configurations to explore how seed networks promote transformations in agricultural, ecological, political, material, social, and cultural realms. We conclude that social innovation arises when the material exchange of seeds is intertwined with interpersonal sharing of knowledge that helps to create new social relationships and reframe global agricultural problems. The materiality of the seed is the intermediary that unites people, ideas, and networks across sectors, and serves as a means to redefine social relationships and create new modes of learning, doing, framing, and organising.