<p>The article is innovative in the way it brings the history of Russian existentialism into dialogue with current debates in two approaches to world politics: “global International Relations” and “ontological security studies”. Both approaches seek to decentre modern politics, dismantle its hegemonic structures without essentialising new borders, and disentangle the individual Self from the traps of national and imperial ontological insecurities. My article advances these debates by introducing a novel conceptual metaphor of the Lonely Self in the oceanic tidepools of international anxiety, unpacked through ideas from twentieth century Russian existentialism and personalism. To theorise such the Lonely Self, I look at four existential dimensions of being: space, time, the authentic Self, and significant political Others. These correspond respectively to the spatial symbol of an ocean in the philosophy of Semyon Frank, Pavel Florensky’s idea of petrified time, the loneliness of the authentic Self in Lev Shestov’s “Robinsonade” philosophy, and Nikolai Berdyaev’s personalist critique of social conformism. The research outcomes challenge the nation-centric critique of war and facilitate the construction of transnational oceanic theory of world politics.</p>