Aldashin (Persian: الداشين) is a village in, and the capital of, Alvars Rural District of the Central District of Sareyn County, Ardabil province, Iran.

At the 2006 census, its population was 695 in 146 households, when it was in Ab-e Garm Rural District of the former Sareyn District of Ardabil County. The following census in 2011 counted 763 people in 216 households, by which time the district had been separated from the county in the establishment of Sareyn County. The latest census in 2016 showed a population of 780 people in 221 households.