64°10.007′N 21°40.714′W

Sundlaugin (Icelandic pronunciation: [ˈsʏntˌlœyjɪn], the swimming pool) is a recording studio located near Álafoss in the town of Mosfellsbær in Iceland known for being the recording and rehearsal location of post-rock band Sigur Rós. The location was originally a swimming pool built in the 1930s which had been abandoned when Sigur Rós purchased it in 1999 and converted it and adjacent buildings into a studio.^[1][2]

The band originally intended to record their third album, titled ( ), in an abandoned NATO tracking base in the northernmost mountain in Iceland, but after inspection decided it was too impractical. Shortly after they found the abandoned pool lot in a rural neighborhood in Mosfellsbær. They bought the lot and transformed it into a studio. In order to fit the massive mixing console into the building, part of the roof was opened up and the console was lowered with a crane.^[3]

Much of the band's photography and artwork is taken from the surrounding landscape, such as the art found on the first album recorded in the studio, ( ).^[4]

The recording studio has also been used for recording, mixing and mastering (usually assisted by the studio's sound engineer Birgir Jón "Biggi" Birgisson) by a wide group of mainly Icelandic artists and bands, including:^[5][6]

• Agent Fresco
• The Album Leaf
• Alcest
• amiina^[7]
• Amusement Parks on Fire^[8]
• Björk^[9]
• Bubbi Morthens^[7]
• Emmanuel De La Paix^[10][11]
• Flying Hórses
• For a Minor Reflection
• Jakobínarína
• Julianna Barwick^[12]
• Langi Seli og Skuggarnir^[13]
• Mammút^[13]
• Mugison^[7]
• Múm^[14]
• Ólöf Arnalds^[15]
• Retro Stefson
• Seabear^[13]
• Self Defense Family
• Sin Fang^[13]
• Ske
• Slowblow^[16]
• Steindór Andersen
• Stórsveit Nix Noltes

As of 2020, Sundlaugin is owned by Sigur Rós keyboardist Kjartan Sveinsson.^[1]