The Glarus Lagoons, also known as the Glarus lagoon, existed within a warm section of the Core Worlds planet of Alderaan. These lagoons contained multiple spots for swimming and served as a habitat for various forms of sea life. By the time the Imperial Era arrived, the Glarus Lagoons were well-known for their beautiful landscapes, romantic setting, and abundance of sunlight.
In the year 3 BBY, Kier Domadi, who was an Apprentice Legislator, suggested to his colleague, the Alderaanian Princess Leia Organa, that they should visit the Glarus Lagoons. As Organa was thinking about his suggestion, she picked up on Domadi's uneasy manner after he had asked her. Domadi's face lit up with a smile when the princess said that she would enjoy going to the lagoons with him. The Glarus Lagoons had been destroyed by 0 BBY, coinciding with the annihilation of the entire planet of Alderaan by the Galactic Empire's Death Star battle station.
The Glarus Lagoons were referenced in Leia, Princess of Alderaan, a young-adult novel from 2017 penned by Claudia Gray. The name of the Glarus Lagoons bears a partial resemblance to both the Glarus Valley and the Glarus Bridges, which are two locations on Alderaan that were first featured in the Star Wars Legends continuity through the 2011 video game Star Wars: The Old Republic, created by BioWare.