This book explores how WhatsApp is transforming multilateral diplomacy. Drawing on real-life exchanges from diplomatic WhatsApp groups—including CARICOM and the UN’s Sixth Committee—it reveals how instant messaging facilitates rapid coordination, fosters inclusivity, and redefines diplomatic communication. The book combines theory and practice, beginning with the evolution of diplomatic communication tools, followed by an empirical analysis of WhatsApp usage by diplomats. It outlines both the opportunities—such as speed and accessibility—and the risks, including confidentiality and power imbalances. With recommendations for optimizing the use of digital platforms in diplomacy, the book offers a timely and unique perspective on how messaging apps are reshaping international cooperation. A valuable resource for scholars, practitioners, and students of international relations, diplomacy, and digital communication.