This article examines the global travels and anti-colonial thought of the Indian revolutionary Manabendra Nath Roy. It focuses particularly on his little explored stay in revolutionary Mexico, where he became a founder of the Mexican Communist Party in 1919. Drawing on archival sources from various countries and Roy's own writings, the article situates Roy's exploits somewhere between a global anti-colonialism, transnational solidarity and diasporic nationalism. It explores particularly the possibilities and the limits of an image of Asia and Latin America as regions united in their oppression by imperialism, and warranting shared anti-colonial strategies in the framework of international Communism.