Lai da Marmorera is a reservoir in the Grisons, Switzerland.

It is part of the Parc Ela nature park.

The lake with a surface area of 1.41 km2 (0.54 sq mi) formed after the completion of the Marmorera dam in 1954 when the old village of Marmorera was flooded.

The lake is flanked on one side by the route of the Julier Pass.

This article related to a lake in Graubünden is a stub.