These are found in ponds, creeks, ditches, and shallow lakes nearly worldwide.

The Siphonariidae on the other hand are unusual in that they have secondarily returned to the sea, and are now sea snails, limpet-like marine gastropods which live in the rocky intertidal zone but which still breathe air and become active at low tide.

Basommatophorans are characterized by having their eyes located at the base of their non-retractile tentacles, rather than at the tips, as in the true land snails Stylommatophora.

The majority of basommatophorans have shells that are thin, translucent, and relatively colorless, and all except Amphibola lack an operculum.

In the older taxonomy of the Gastropoda (Ponder & Lindberg, 1997) the suborder Basommatophora consisted of the families : The informal group Basommatophora contains the following superfamilies and the clade Hygrophila (according to the Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)): The family Ancylidae has been reduced in the new taxonomy to the status of tribe Ancylini Rafinesque, 1815 of the subfamily Planorbinae Rafinesque, 1815 of the family Planorbidae Rafinesque, 1815.