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

Langwies is first mentioned in 1384 as die lang Wise.

Before the merger, Langwies had a total area of 54.9 km2 (21.2 sq mi). Of this area, 48.8% is used for agricultural purposes, while 22.6% is forested.