Autonomous profiling buoy system was developed for continuous monitoring for the ice-covered oceans. This profiling buoy is tethered to a fixed floating point to collect time series of vertical profiles by controlling its buoyancy. The profiling buoy is equipped with satellite data transmitter together with oceanographic sensors, so that it can send the observed data near real-time basis at the timing of surfacing. Field experiments of this profiling buoy system were conducted at about 400-m deep region in the Okhotsk Sea for a month from July to August 2014 and for six months from November 2014 to May 2015. Designed functions including measurement, data transmission, and ice-avoiding protocol were successful. At the same time, problems such as limited ascent for the high-speed current were revealed for future improvements.