This article explores the intersections and resonances between unmaking and more-than-human design. We begin by aligning unmaking with decentering, a fundamental practice in more-than-human design, through their shared movement and materiality. Using Lindström and Ståhl’s notion of the double movement in un/making, we analyze a series of workshops focused on designing with AI, annotating what was un/made and de/centered during the workshops’ activities. Through this analysis, we introduce two key contributions that highlight some opportunities in the diffractive alignment between unmaking and more-than-human design: firstly, the notion of ‘unmaking-with’ as an emergent concept to describe a posthumanist unmaking practice, and secondly, three decentering tactics–situating, materializing, and enacting–that instantiate this practice through design. Finally, we discuss how unmaking can enrich more-than-human design and, conversely, how more-than-human design can help define the epistemological scope of unmaking.