A reliable recovery system is crucial to marine instruments for effective observations and data acquisitions. The communication beacon between the instrument on the sea and the scientific research ship is a key part of the recovery system. The low-power marine instrument recovery communication beacon designed in this paper is a set of lightweight beacon machines that can be used for marine instrument recovery. The system integrates a global position system (GPS) positioning module and a Lora low-power long-distance communication module. The system can automatically switch to the standby mode while it float up. The system can work continuously for 48 h. Under the low-power standby mode, the theoretical standby time is over 5 years. Once the instrument floats up, the location information can be sent to the nearby ships. The effective communication distance can reach 7 km. The system can bear the pressure up to 9 000 m water depth. Power consumption test and communication test showed that, the proposed instrument has low power consumption, high positioning accuracy, high reliability, and long communication distance.