Koshimizu (小清水町, Koshimizu-chō) is a town in Okhotsk Subprefecture, Hokkaido, Japan.

As of May 1, 2017, the town had an estimated population of 5,029 and a population density of 18 persons per squared kilometre.

Koshimizu's mascots are Hogaja (ほがじゃ) and Denbo (でん坊).

They are appointed as mascots on October 3, 2013.

This Hokkaidō location article is a stub.