Background: Opisthorchis felineus and Metorchis bilis are trematodes that cause opisthorchiasis and metorchiasis, respectively. The freshwater snails Bithynia hispanica and B. tentaculata are the respective intermediate hosts for these parasites in the Iberian Peninsula, where both parasites are present. Methods: To study the distribution of these snail species, an exhaustive literature review and revision of museum collections was performed. Results: A total of 370 localities were compiled and mapped. B. tentaculata were found throughout the Iberian Peninsula, both in Spain and Portugal, while B. hispanica was found only in the Mediterranean coast of Spain. Conclusion: Knowing the distribution of the Bithynia species found in the Iberian Peninsula is highlighted in terms of public health, as the presence of the snail is related to the presence of the disease and can be used as a tool to face future outbreaks.