PurposeRecent substantial developments of consumer-to-consumer social commerce platforms (C2C-SCPs) emboldened consumers/users to be involved as sellers. Considering C2C social networks that privilege local reach, this paper aim to explore how the practice-based view informs non-professional sellers' involvement.Design/methodology/approachUnderpinned by data from 29 semi-structured interviews with non-professional sellers on Kaskus, one of the largest local Indonesian C2C-SCPs, the study reveals the emergence of a novel structural practice that we call casual selling.FindingsThe findings show that casual selling allows non-professional sellers' involvement in C2C-SCPs through three broad categories of practices: priming oneself, producing commercial operations and valuing others. Within these three categories, non-professional sellers are found to generate both personal and collective involvement along nine situated market practices.Research limitations/implicationsThis paper adds to previous research by introducing the practice-based view to social commerce literature. In doing so, it deals with the under-investigated seller's perspective and activities that prevail in C2C-SCPs.Originality/valueIn C2C-SCPs, casual selling constitutes a distinct mode of involvement in social commerce in which established professional selling standards are suspended. As a structural practice, it entices non-professional sellers to consider a wider variety of situations in which they are in dialogue with other individuals (buyers and sellers) to shape s-commerce potential. In doing so, C2C-SCP users draw on a dynamic intertwining between digital technology and the socio-cultural environment surrounding s-commerce.