Many of the world’s languages are endangered or vulnerable. For some of these languages, a presence in technological domains can illustrate vitality and demonstrate relevance to the lives of younger speakers. A presence on social media is often seen as particularly significant for younger speakers due to their high levels of social media use. This article explores the presence of Cymraeg (the Welsh language) on TikTok. Through the analysis of a corpus of 200 videos, the article reveals a complex and richly bilingual content space with considerable intermingling of Cymraeg and English. Commenting on videos and engaging in a text-based conversation with the content creator and other audience members is shown to be a significant activity. The corpus demonstrates that Cymraeg is being used, taught, discussed and promoted on TikTok. This article contributes to an ongoing assessment of the digital vitality of Cymraeg and extends our understanding of the role that social media can play in supporting the sustainability and vitality of minority languages.