This article proposes the examination of the climate politics of labour unions, particularly the strategy of just transition, through the prism of environmental labour studies, an ecosocial approach to labour environmentalism. In the first part, it presents a historical overview in order to highlight how the just energy transition became a central element of labour environmentalism. The paper then examines the double impact of climate politics and just transition on labour environmentalism – narrowing its substantive focus while deepening the intersection of nature and labour within and beyond the workplace. The second part draws on the environmental labour studies approach to propose that labour environmentalism should take into account the inseparable relationship between labour and nature, expand the scope of work and workers, and account for global divisions of labour. In our view, such a programmatic shift will ensure that work and workers are placed centrally within ecosocial politics.