Der Rotsee ist ein 2,5 Kilometer langer und schmaler See nahe der Stadt Luzern im Schweizer Kanton Luzern. Das Gebiet des Sees ist ein Naherholungszentrum, die Uferbereiche sind Naturschutzgebiet.

The Rotsee is a natural rowing lake on the northern edge of Lucerne, Switzerland. It is 2,400 m long with virtually no current and protected from winds by nearby hills making it an ideal rowing venue.
The first regatta was hosted here in 1933 and since been the venue of a large number of international rowing events (including the first ever World Rowing Championships).
The lake is traditionally the venue for the final leg of the Rowing World Cup series. Although when a World Championships is also being held in Lucerne (as happened in 2001) then no World Cup Race is held on the lake.