In 1902, eight northern European nations formed the International Council for the Exploration of the Sea (ICES). A turn-of-the-century international movement created opportunities, funding, and political support for marine science. This paper uses ICES as a lens for examining international cooperation, and shows how its sponsors benefited from the intersection of internationalist ideals, national interest, and the characteristics of the marine environment. Marine science is then compared to other field sciences to explore how these three factors promoted internationalism in science (...) more generally. (shrink)