This work presents an overboard localization system based on measuring the received signal strength indicator (RSSI) between smart lifejacket tags and one interrogator station mounted inside an unmanned aerial vehicle (UAV). Localization is based on weighted least mean squares (LMS) algorithm. Simulations that study the effect of the UAV search path on the localization accuracy are presented and it shows that the parallel tracks search path gives better localization results compared to other search paths. Measurements are carried out in a search area of 500 m × 350 m, where tags are localized with a mean error of 37.5 m. The measurement results show better localization accuracy compared to other RSSI based localization algorithms.