This paper argues that the anti-utopia (as distinct from the dystopia) is an important but neglected part of the political landscape. The anti-utopia represents a place which, simply by existing, is intended to make either specific utopias, or the wider project of utopianism, impossible to realise. My focus in this paper will be on the project of neoliberal seasteading, which aims to create new communities at sea. Neoliberal seasteading is widely portrayed as an attempt to create marine utopias, and especially what I call "utopias of escape". I argue that neoliberal seasteading actually aims at the creation of anti-utopias. Its goals are much more ambitious than has been recognised. Rather than creating utopias for a privileged few, neoliberal seasteaders want to transform the wider world, making progressive visions of democracy and redistribution impossible.