The data show concentrations of total mercury (THg) in hair from female adult (>4 years, n= 185) and sub-adult (1-4 years; n= 14) polar bears from the Barents Sea subpopulation management regime. The samples were collected in spring of each year between 1995 and 2016 (except 2001 and 2002). Additionally, the samples were analysed for stable isotopes of carbon (δ13C), sulfur (δ34S), and nitrogen (δ15N) to approximate feeding habits (δ13C and δ34S: marine vs. terrestrial diet, δ15N: trophic level). It was assumed that δ34S could be a potential indicator for bacterial mercury methylation. The data were used to explore temporal trend of THg, and how they were affected by changes in feeding habits, and changes in body condition, breeding status, and age. The THg concentrations are given in µg/g hair; and values of all stable isotopes in ‰. Polar bear length and girth are given in cm, and weight in kg. Breeding status refers to females captured alone (n), with cubs of the year (c), or with one or two year old offspring (y, 2y).