Sea ice density is an important engineering and geophysical parameter. However, it lacks a standard method of measurement. In this paper, we show that the hydrostatic weighing method is the best available method that can capture the natural variation of the ice density throughout the ice thickness below the water line. The hydrostatic weighing method has a lower measurement uncertainty (0.2%) in comparison with the most common mass/volume method, which has an uncertainty of 4% when applied to ice samples with lengths and diameters of similar to 70 mm. The density of first-year level ice below the waterline measured by the hydrostatic weighing method in the present study lies in a range of 894-921 kg m(-3). The density of rafted multiyear ice and the ice above the waterline had a wider range, 863-929 kg m(-3). (C) 2016 Elsevier B.V. All rights reserved.