Globalization is classically defined as the increased movement of people, goods, and information around the world. Yet not all aspects of globalization and deglobalization happened simultaneously. This article uses the development of an international health information network to explore why information did not globalize concurrently with migration and trade. Nearly seven decades after states had understood disease as a cross-border problem, the League of Nations Health Organization (LNHO) brought together states, empires, and foundations in a voluntary exchange of health information that reached two-thirds of the world’s population and outlasted the League itself. The LNHO organized an infrastructure based on new wireless technology around colonial networks, port cities, the sea, and the air. Singapore and Saigon were more central than Geneva. Health information was meant to prevent epidemics; it enabled the LNHO to justify its own existence as a neutral broker for standardized, technical information; it helped colonial powers like Britain and France to share the financial burden of empire; it provided others like Japan with military advantages; and it enabled Germany to participate in international endeavors to regain national prestige. Tracing such infrastructures enables historians to overcome artificial divides between the national, international, imperial, and global.