The agency will support Vodafone's business-to-business comms across Europe, Asia Pacific, Africa and the US.
The firm initiated a global review of its international b2b PR support earlier this year, led by group comms director Matt Peacock and head of enterprise and industry analyst comms Nicola Rossie.
The brief, thought to be worth a six-figure sum, calls on Text100 to provide strategic planning, global campaign management and local tactical support.
The agency will target a wide range of enterprise audiences in more than 70 markets - from small offices to multinational corporations.
Enterprise accounts generate a quarter of Vodafone Group's global revenue, and the company now serves more than 30 million business customers around the world.
The appointment follows the completion of Vodafone's £1bn takeover of Cable & Wireless Worldwide, the telecoms group that focused on business and public sector clients.