ABSTRACT The Thai 2020 anti-government protests were the first large-scale pro-democracy protests in Thailand mediated on Twitter. How has Twitter been used by anti-government supporters and to what effect? This article examines the use of hashtags by activists during the early stages of the Thai 2020 anti-government protests. Using an original dataset of 27,233 Twitter data points drawn from the #FreeYouth (FYM; #เยาวชนปลดแอก) campaign, the article argues that Twitter was used primarily to build collective narratives and disseminate movement information, rather than to mobilize offline protest activities. The key topic conversations within the Free Youth networks focus on discontent towards the government and demands for democracy, suggesting that Twitter was central to mobilizing pro-democracy collective action frames. The article further argues that the Free Youth networks on Twitter were loosely connected through community clusters of weak ties, not tight crowds. The challenge for FYM activists going forward is to support ties across its online networks that will strengthen over time, or risk becoming an ephemeral network of convenience that can only be mobilized on an ad hoc basis.