Abas was a demigod and a son of Poseidon and a mortal named Arethusa.
Abas was the son of Poseidon and Arethusa. A Thracian by birth, Abas founded a tribe known as the Abantians or Abantes. Abas and his Abantian followers migrated to the island of Euboea, where he subsequently reigned as king. He was father of Canethus and Chalcodon, and through the latter grandfather of Elephenor, who is known to have accidentally killed him. Also given as Abas' children are Alcon, Arethusa and Dias, of whom the latter was said to have founded a city Athenae on Euboea.