Total Electron Content (TEC) is one of the most important parameters of the ionosphere for propagation of radio waves. TEC is now being routinely monitored by global GNSS networks almost everywhere on Earth except geomagnetic poles. In order to study TEC evolution near the southern magnetic pole, two series of GNSS observations were carried out at the Vostok Antarctic station. Every of the two series lasted about one year each, 2016 and 2018. The collected GNSS observations were processed with RTKLIB and GeNeSiS software packages. TEC was estimated both from code and phase observables. The resulting TEC time series were analysed and compared to the global TEC map. These results may potentially augment our knowledge about ionosphere structure and evolution near the geomagnetic poles. As a continuation of this study a permanent GNSS receiver is considered to be installed at the Vostok Antarctic station.