De Fluezen, also spelled Fluessen, is a large lake in the southwest of Friesland, Netherlands, forming part of the extensive Friese Meren lake system. It covers approximately 1,100 hectares (2,718 acres), making it a significant expanse of open water. The lake is characterized by its substantial size and is often paired with the nearby Sleattemer Mar on popular routes. The area is a hub for water sports, and paddlers will share the water with motorboats, sloops, and sailing vessels, particularly in the lively centers of villages like Woudsend and Balk. These towns are accessible via connecting waterways and feature openable bridges, which are important for route planning.

A notable 34-kilometer sailing route, suitable for paddling, circumnavigates De Fluezen and the Luts waterway. This route offers variety, taking paddlers across the open lake, through forested stretches on the Luts, and directly through the village centers. Completing such a route at a typical touring pace is considered a full-day undertaking. For multi-day trips, the lake offers opportunities for overnight camping, with islands providing potential shelter. The area is recognized for its birdlife, making it a destination for birdwatching from the water.

Regarding regulations, general boating is permitted, including the use of kayaks and canoes. Paddlers should be aware of the main navigation channels used by commercial shipping and are advised to stay clear of them for safety. While fishing is a popular activity on the lake, requiring a VISpas permit, this does not generally restrict paddling. The water body's aesthetic is defined by the classic Dutch lake landscape, combining open water vistas with access to historic Frisian villages.