Hamatonbetsu(浜顿别町,Hamatonbetsu-chō) is a town located in Esashi District, Sōya Subprefecture, Hokkaido, Japan. As of 2013, the town has an estimated population of 4,066 and a density of 10 persons per km². Hamatonbetsu is in a long period of sustained population loss. The total area is 401.56 square kilometres (155.04 sq mi). Hamatonbetsu's claim to fame is its freshwater Lake Kutcharo, a world famous wetlands area home to thousands of swans making their winter migration from northern Siberia to the southern climate of Japan.