Molinis is a former municipality in the district of Plessur in the canton of Graubünden in Switzerland . On 1 January 2013 the former municipalities of Molinis, Calfreisen , Castiel, Langwies , Lüen , Peist and St. Peter-Pagig merged into the municipality of Arosa .

Molinis is first mentioned in 1335 as Mulina. Formerly, in Romansh, it was known as Molinas.

Before the merger, Molinis had a total area of 13.2 km2 (5.1 sq mi).