The Arctic and Antarctic have attracted their own distinct regional projects and expressions of regionalism. At a conceptual level, our discussion is informed by a desire to better understand how ‘territory’ and ‘region’ are put to work discursively and acted out and upon geopolitically. In the Polar Regions, in particular, the intersection of ice, rock and water is particularly distinct in terms of how territorial and regional management is expressed. Working off a volumetric, rather than areal, focus, recent work alerts us to how region-making projects have worked through height, depth and subterranean domains none more so than in the Arctic and Antarctic. It is also axiomatic that the regional boundaries of the Arctic and Antarctic are fluid so that it is imperative that we appreciate that regional and international actors such as the European Union (EU) and UN agencies such as the International Maritime Organization (IMO) play a part in shaping polar regionalism in the water, air, and on the land.