Sensors are increasingly collecting data everywhere, changing how we relate to and manage the environment. These data answer scientific questions of researchers, but can also generate social, cultural, and political effects, reinforcing the need for data in near real time. In this work, a low-power, scalable, and sustainable communication solution based on LoRa is proposed to develop an oceanographic monitoring system composed of water quality monitoring buoys that can measure, among others, parameters such as water temperature, chlorophyll-a, turbidity, oxygen concentration, etc. An exhaustive evaluation is carried out with a real test bed in a 135 Km 2 coastal lagoon, demonstrating that our proposal offers good performance in terms of transfer time and latency, energy consumption, and range, showing good scalability with the number of buoys added.