The Loisach is a river in Tyrol, Austria and Bavaria, Germany. It is a tributary to the Isar. The source of the Loisach is near Ehrwald in Austria. The Loisach flows past Garmisch-Partenkirchen and into the Kochelsee . The Loisach then flows out of Kochelsee and joins the Isar at Wolfratshausen. A canal joins the Isar and the Loisach enabling boat traffic to avoid the bridges at Wolfratshausen.