Anthas was a demigod and a son of Poseidon.
Anthas was the son of Poseidon and Alcyone, and brother of Hyperes. The brothers were the founders and first kings of the cities Hyperea and Anthea in a region they reigned over; later on these two cities were merged into the historical Troezen. Anthas was father of at least two sons, Aëtius and Dius, of whom Aëtius was the successor to both his father and uncle, and further co-ruled with Pittheus and Troezen. The descendants of Anthas through Aëtius reputedly founded colonies in Caria: Halicarnassus and Myndus.