Sonobuoy is a sensory device collecting underwater acoustic signals and transmitting them to some base stations via RF waveforms. In this paper, newly developed Turkish sonobuoy project's sea performance is presented. The proposed system architecture has been developed as a prototype in the lab environment. Lab experiments have been conducted successfully over a test bench representing typical submarine detection case. These experiments are designed to calibrate sensory system and optimize the RF transmission. The sonobuoy system has been used in open sea environment for the similar submarine scenario. The bearing angle representing submarine position has been detected within +/- 10 degrees accuracy as required. We, then, compared the lab and experimental open sea results that were identical.