Mountain climbing activities carry high risks to climbers’ safety, especially in cases of getting lost, injuries, or other emergency situations. The absence of a real‑time monitoring system is one of the factors that increases these potential hazards. This study aims to design and develop a mountain climber group monitoring system based on the
Internet of Things (IoT), integrated with a web dashboard and utilizing the Message Queuing Telemetry Transport (MQTT) protocol to optimize data transmission. The system consists of IoT devices used by climbers to periodically send location and environmental condition data to a central server. The data is then visually displayed through a web dashboard that can be accessed by the monitoring team. The development method used is prototyping, starting from requirement analysis, system design, implementation, and testing. The test results show that the system is capable of transmitting data with low delay, providing accurate visualization, and offering a responsive dashboard interface. An important finding is the effectiveness of the MQTT protocol in reducing network load and speeding up data transmission, resulting in more efficient monitoring of climber groups. With these advantages, the system is expected to be a practical solution for enhancing safety and coordination in mountain climbing activities in real time.