Abstract: A transportable, disassemblable lavatory cabin is provided and includes a plurality of wall segments, optional ceiling and floor segments, and at least one tension strap extending around the exterior of the wall segments to provide a stable, closed construction which can be assembled quickly and without the need for tools. To facilitate the manufacture, transportation, and installation of the cabin, as well as to permit mass production, the wall segments are at least partially manufactured as demoldable, hollow blow moldings with substantially the same outer ground plan. This permits the wall segments to be stacked for easy transportation. Each of the wall segments is manufactured to have a first wall part which is substantially straight on its outside in ground plan and at least one second wall part firmly connected to the first wall part and preferably formed at an angle of 60.degree. thereto.