A two-year study was conducted on the growth processes of sea ice in Ongul Strait, Antarctica. Routine measurements of snow depth and ice thickness were made and sea-ice cores were collected to assess their structure, temperature and salinity. The snow depth varied from 0 to about 1 m. In the winter months, the growth rate is higher in bare-ice regions than in snow-covered regions. However, over the year, the ice thickness itself is lower in the bare-ice regions than in the snow-covered regions. Sea ice in the snow-covered regions increased in thickness in spring rather than in winter, due to the formation of snow-ice and by ice formation related to the melting of snow cover.