One was the son of Poseidon, granted by his father the power to walk on water. Euphemus's mother is variously named: Europe, daughter of the giant Tityos; Oris, daughter of Orion; or Macionice, daughter of Eurotas. His residence is given as Panopeus in Phocis, or Hyria in Boeotia, or Taenarum in Laconia. Euphemus joined the voyage of the Argonauts, and served the crew well as helmsman. By a Lemnian woman (Malicha, Malache, or Lamache) he became the father of Leucophanes. Medea prophesied that he would one day rule Libya; her prophesy came true when Battus of Thera, an alleged distant descendant of Euphemus (by 17 generations), founded Cyrene.
Euphemus is also a character in the work by Thucydides in the Peloponnisian War.
bg:Евфем ca:Eufem (fill de Posidó) cs:Eufémos de:Euphemos el:Εύφημος es:Eufemo eu:Eufemo fr:Euphémos fils de Trézène id:Eufemos it:Eufemo (Poseidone) lt:Eufemas hu:Euphémosz ja:エウペーモス pt:Eufemo ru:Евфем uk:Евфем