The municipality is located on the alluvial land called Bödeli between Lake Thun and Lake Brienz. It is across the Aare to the north from the town of Interlaken. It consists of the historic town of Unterseen and its urban village-like settlements, rural parts closer to the Lake Thun including several camping sites, some with beaches, a golf course on the Unteres Stadtfeld, and scattered settlements and woods on the nearby steep mountainside of Dälebode, Chienberg and Harder (Vordere Harder, Hintere Harder, Luegiwald).