Water security aims to provide safe, reliable, affordable and sufficient water for people, agriculture, industry and ecosystems, subject to societal choices across related trade-offs and risks. Managing resource risks, delivering effective governance, promoting financial sustainability and achieving social equity are central to achieving water security. We explore how innovations in mobile communications have created an inclusive, secure and low cost architecture for financial and data flows to reduce risk and enhance water security. In Africa, water security challenges associated with climate extremes and population growth outstripping improved water services’ access are juxtaposed with its global lead in mobile commerce innovations, including mobile water payments. Market driven expansion of mobile network coverage and low cost, mobile handsets mean more Africans will be connected to mobile phone services than those receiving improved water services in 2012. The confluence of rapid mobile network expansion, mobile phone ownership, mobile water payments and smart metering technologies offer new policy pathways to water security to accelerate progress on sustainable, safe water access, particularly for those in the greatest need and those most difficult to reach. We chart emerging mobile water innovations in Africa and policy implications in the region and beyond.