Purpose This paper explores the ways in which a range of company-level trade unions based in Chile's food manufacturing industry engage with Internet technologies and social media. Design/methodology/approach The research has a qualitative methodology with 69 semi-structured interviews conducted between 2015 and late-2019 with different level informants such as trade union leaders, human resource managers, line managers, labour lawyers, academics and field experts. Findings The findings suggest that these trade unions' engagement with social media was not widespread, using it to share communication of day-to-day activities with members. The article argues that even in contexts where there appear to be some radical union traditions, a trade unions' identity, as well as the nature of the employment relationship, can have a constraining effect regarding how unions use digital technologies and social media. Practical implications The article suggests new ways for Chilean trade unions to take the opportunities offered by digital platforms and social media to enhance the representation of their workers' collective rights while advancing the labour movement's agenda. Originality/value The paper makes a direct contribution to the literature on Internet technologies, social media and the labour movement, while expanding the empirical evidence on the topic and looking at the limitations and constraints on the use of social media in this context. Given the current discussion in academic settings as well as within the union movement about the importance of social media for trade union revitalization, the present paper focuses on building empirical research in a less known context (i.e. Chile).