The Swiss Confederation joined the international Rhine regime remarkably late but vigorously, with Basel becoming one of the Upper Rhine’s central ports. In the shades of Prussia’s decline during the First World War, the Confederation promoted itself as a shipping nation, joined the Zentralkommission in 1919, and even actively took part in the planning of the Canal d’Alsace together with France in the late 1920s. This chapter traces the role of the Swiss Confederation within the international Rhine regime and the Zentralkommission from the late nineteenth through to the second half of the twentieth century.