Islands have long been privileged objects of spatially oriented literary analyses. Along similar lines, oceanic space has been studied through various spatial concepts, from Margaret Cohen’s ‘chronotopes of the sea’ to recent work in the so-called blue humanities and critical ocean studies. Responding to and complementing these critical trends, this chapter argues that islands and oceanic space have not only provided highly interesting case studies for the ‘application’ of spatial literary and cultural studies, but have themselves been at the heart of spatial theorising – from the fragmentation of mediaeval spatialities in the early modern isolario to Benoît Mandelbrot’s conceptualisation of fractal geometry through the figure of the island. Islands and oceans have also been central to Indigenous and Creole spatial poetics and philosophies; Édouard Glissant’s use of the Caribbean archipelago as a key figure for his poetics of relation is a case in point. Ultimately, then, this chapter is not primarily interested in what spatial theory can teach us about islands and oceans, but in what islands and oceans can teach us about space – and in how the poetic and narrative presence of islands, oceans, and archipelagoes in cultural texts has actively shaped and challenged wider assumptions about space.