The long-term mean harmonic and nonharmonic tidal characteristics and their seasonal changes were estimated for six tide-gauge stations in the Russian Arctic (White, Laptev and Chukchi Seas). The estimation is based on hourly sea level observations. Significant differences in the seasonal variations of the amplitudes and phases of major tidal constituents were found between the White Sea and the seas of the Siberian continental shelf. In the White Sea, they do not exceed 9%, while in the Siberian continental shelf seas they reach 63%. The results of calculations of the tidal extreme characteristics, such as the mean spring range and the maximum possible tidal range, are given.