Euphemus is from Taenarum. He is an expert swimmer. During the events of Jason and the Argonauts (1963) Euphemus competes in Jason's Olympic Games and earns a spot on the Argo. He then travels with the Argonauts to find the Golden Fleece. After Jason's duel with Acastus, Euphemus jumps into the sea to go after Acastus who jumped overboard. He struggles with Acastus but is killed by him.