In some sports, where the athlete is training alone or far from its coach, it is often difficult to gather real time data about the athlete’s performance. Additionally, coaches also find difficult to communicate with their athletes in order to improve their training effectively. Amongst those critical sport activities, swimming is one of the most challenging, not only due to the distance between athletes and coaches, but also due to the harsh environment where the swimmers are immersed. It is known that real-time data about the swimmers training sessions, in term of biological signs and physical performance, is a valuable asset to help guiding successful training practice. Although several devices and techniques are available to monitor such data, normally the acquired data is stored in a portable device for later analysis, due to the transmission issues related to the harsh environment of the pool. Such transmission issues are often related with the location of the antenna, which is surrounded by water. In this paper, we propose a radiowave communication system, which makes use of LoRa to overcome the huge attenuation caused by the pool water. The proposed communication method, also mitigates the signal loss induced by the swimmer turns and some swimming styles where a single antenna might me deeply immersed or covered by the swimmer body. The radio communication that employs a signal frequency of 433MHz, has been successfully tested for all swimming styles, turns and at various deepness levels in the underwater phase, with very good results in terms of received signal level and capability to maintain the radio link in multiple different conditions.