Users of public transportation often face uncertainty regarding vehicle arrival times, leading to inefficiencies in daily commutes. This study presents the development of a mobile application for real-time trolleybus tracking within the Adolfo López Mateos Professional Unit circuit in Mexico City, based on a client-server architecture. It employs mobile devices equipped with GPS and communicates via UDP sockets for efficient coordinate transmission. The system consists of two modules: the trolleybus application (server), which collects and transmits GPS data to the central server, and the user application (client), which processes and displays location data using the Google Maps API, in addition to estimating arrival times. The system was developed in Android Studio with Java, using Firebase Cloud Messaging for real-time notifications. Testing validated GPS accuracy, transmission latency, and power efficiency. Response times of less than one second were recorded under specific conditions. This system provides a scalable solution for the digitization of university transportation, optimizing mobility within the campus.