Bottensjön is a lake in Karlsborg municipality in Västergötland and is part of Motala Stream's main catchment area. The lake is 13 meters deep, has an area of 12.1 square kilometers and is 88 meters above sea level. The lake is part of Göta Canal and is located between Viken and Vättern.
Outstanding fish species are perch, gosh, pike, whitefish and signal crayfish.
KFFF is a sports fishing club that manages the fishing card sales in Bottensjön through BOFO, which is the organization of all fish owners in the Bottensjön.