This chapter explores how contemporary children and youth climate activists utilize or challenge dominant childhood figurations in climate change discourses. Through digital participant observation, I study the global online participatory culture of Fridays for Future communities on Instagram. What forms of visual rhetoric do grassroots activists use to gain visibility and what forms of childhood political subjectivities are represented? The analysis shows that the activists use various strategies to create visually dramatic images, ranging from humor to competence, from anger to joy, and from mass-demonstrations to artistically creative small-scale strikes. The chapter argues that such visual rhetoric is embedded with certain figurations for the children and youth activists such as (1) the child speaking truth to power, (2) the global mass of children and youth, (3) the competent and responsible children and youth, and (4) the humor and creativity of activism. I suggest that these figurations both make use of adultist perceptions of children and youth for strategic purposes and that they also challenge passive and futurist figurations of children in climate discourse by emphasizing the present power of children and youth.