A survey of the exchange of freshwater gastropods mollusks between Europe and North America is provided. Several dozen species of snails migrated, during the last two centuries, in either direction across North Atlantic and this process is ongoing. The intensity of the faunal exchange is unequal since much more snail species have dispersed from North America to Europe than in the opposite direction. Two cases of “failed” invasions of North American lymnaeid snails to Europe are discussed. A species of pulmonate snails, Ampullaceana balthica (Linnaeus, 1758), is reported here as new for the malacofauna of Canada (and for the whole North America). This snail of European origin was found in June 2019 in a small lake in the vicinities of Rimouski Town (Québec, Canada). The taxonomic identification of the mollusks was confirmed by molecular analysis, with the studied specimens having two unique COI haplotypes, hitherto not found in Europe.