Young people mitigate their climate distress, develop their efficacy, and contribute to the effectiveness of climate movements through activism. However, they are often excluded from adult-led climate movements and exposed to a number of risks when they do participate. In this context, this participatory action research study draws on multiple care theories to offer collective care praxis through which adults and young people might co-create more care-full and safe climate justice movements capable of supporting, sustaining, and sharing power with young people. The study examines how 13 young and three adult co-researchers learned about and applied collective care through a youth climate justice training program in Western Australia. The program enabled young people to engage with climate emotions, identify care practices, and map support networks. Furthermore, the study developed three practices for adult-led climate movements engaging with young people: Responding to intersectionality with active solidarity, child safeguarding, and building care-full community coalitions. We conclude that a collective care praxis offers organisers and activists in all their diversities an opportunity to prefigure more care-full and just climate movements.