Caopatina Lake is a freshwater body of the southeastern portion of Eeyou Istchee James Bay (Municipality), in Jamésie, in the administrative region of Nord-du-Québec, in the province of Quebec, in Canada.

The hydrographic slope of Lake Caopatina is accessible through the forest road R1032 (North-South direction).

The surface of Caopatina Lake is usually frozen from early November to mid-May, however, safe ice circulation is generally from mid-November to mid-April.

In the past, this body of water was designated in various toponymic forms: Kaopatina, Kaopatnaginsckao and Lac de l'Épinette Rouge.

[2] The toponym "Lac Caopatina" was formalized on December 5, 1968, by the Commission de toponymie du Québec, when it was created.