The very definition of the seabed is political by other means: a phrase borrowed from Latour (2004). While the seabed contains geology and biology: blurring the life and non-life distinction, current efforts to transform the seabed into a heavily infested human activity centre one’s vision on its geological characteristics. It employs specific technical measurements relying on geometrics and often undermines the biometrics of the seabed. For instance, the increasing development of undersea cables and offshore tin mining operations in Indonesia rely on geological metrics such as seabed textures, substrates, and sediments. Meanwhile, it erases living organisms in the process of calculative measurement: thus, converting the seabed into a lifeless environment for extractivism. In this matter, the materiality of the seabed has become a geo-strategy and tactic to reign the political agenda of governing the seabed because the hard-to-access seabed requires expensive techno-scientific infrastructure, often owned by a minuscule group of capitalist telecommunication and mining corporates. This way of problematizing the onto-epistemology of the seabed provides a thought-provoking reflection on the politics of the unwieldy underworld: the seabed.