This work is aimed to study, design and build a bus localization system with automatic route register and real-time tracking, accessible through a mobile application. The solution uses Amazon AWS for cloud backend, unifying GPS transmitted data from buses to Android applications. The terminal installed in the bus consists in a Raspberry Pi™ using a GPS receiver and HSDPA module for data transmission. The transmitted data is received in the Android application, and is plotted in real time using Google Maps™, allowing the user to know where his desired bus is, and even to know its point on its route.