ABSTRACT This paper introduces empirical research on tin divers’ bodily experience of seabed mining concerning offshore Bangka and Belitung Islands, Indonesia, critical seabed mining sites. To govern the seabed off these Islands, ‘classic’ geopolitical approaches such as marine spatial planning (MSP) and the Organisation for Economic Co-operation and Development (OECD) hierarchically construct the seabed through two-dimensional mapping and policy, occluding specific tin diving practices on the seabed. Moving from such flat geopolitical understandings of the ocean floor, this paper offers new engagements with feminist geopolitics, volumetric territory and social ocean studies to think about the seabed through its volume, the bodies that are immersed within and animate it, and its geologic materiality. It does so by examining intimate tin diving relations between human bodies, volumetric space and ore bodies in relation to the contemporary geopolitical making of the seabed territory. Whilst many scholars have engaged with this volumetric-embodied-geologic approach, this paper argues that the nexus of volumetric space, bodies (embodied experiences) and geologic materiality in tin diving are a crucial tactical point for diverse mining governance actors, sustaining dangerous labour, mining accidents and death in tin diving.