A unique investigation of the transpacific steam network of Mexico, Britain, China, and Japan. During the nineteenth century, the Trans-Pacific world underwent a profound transformation due to the transition from sail to steam navigation that was accompanied by a reconfiguration of power. Steamships across the Pacific explores how diverse Mexican, British, Chinese, and Japanese interests participated, particularly during Porfirio Díaz's presidency at the peak of Mexico's participation, in the steam network. It investigates this network in its 1860s outset through a time of many revolutionary changes, including the World War, the Mexican Revolution, the opening of the Panama Canal, and the introduction of a new maritime technology--vessels run by oil. These transoceanic exchanges, generated within these new geographies of power, contributed not only to the formation of a Trans-Pacific region but also to the refashioning of the Mexican national imaginary. With transnationalism, global, and migration studies as its main frameworks, this study draws upon a dazzling array of primary sources to center Mexico's Trans-Pacific relations and the influence they wielded over the region at the height of the steamship period.