This chapter explores the relationship between communications technology and public diplomacy and includes discussion of ‘frontier’ usage of innovations over the last two centuries. Beginning with the telegraph, the argument here is that diplomacy has always attempted to integrate technology into its consistent ambition around the maintenance or expansion of the power of the source. To this end, the chapter is keen to point out that we should not think of public diplomacy within arguments of technological determinism. The chapter provides interesting anecdotes from around the world and covers the telegraph, telephone, radio, television, satellite communications, the World Wide Web and social media.