Bithynia siamensis is a species of a freshwater snail with a gill and an operculum, an aquatic prosobranch gastropod mollusk in the family Bithyniidae.

[1][3] This species occurs in: The population of Bithynia siamensis fluctuates during the year.

[4] Bithynia siamensis serves as a first intermediate host for Southeast Asian liver fluke Opisthorchis viverrini.

[2] The number of excretory cells of the digestive system is increased in infected Bithynia siamensis.

[5] Parasites of Bithynia siamensis include trematode Multicotyle purvisi.