How and when might data journalism be viewed as a form of “data activism”? Data activism has been conceptualised as a set of practices which “interrogate the fundamental paradigm shift brought about by datafication”, including through resisting surveillance and mobilising data to denounce injustice and advocate for change (Milan and van der Velden, 2016). In this chapter we examine how data journalist practices might serve not just to reinforce and reify dominant regimes of datafication, but also to interrogate them and make space for public involvement and intervention around data infrastructures. We examine three ways in which such practices may be construed as interventions around datafication: (1) assembling data publics; (2) making data differently; and (3) investigating datafication. Attending to such practices may contribute to the understanding of emerging sites, objects and action repertoires of data activism.