The A1 Ethniki, often referred to as the Greek Water Polo League, is the highest professional water polo league in Greece. It is run by the Hellenic Swimming Federation. It is considered one of the top national leagues in European water polo, as its clubs have made significant success in European competitions. Ethnikos Piraeus and Olympiacos Piraeus share the most championships, having 38. Ethnikos also has the record for consecutive championships, with 18.

History

Title holders

Titles by club

• The 1969 Championship was shared between Olympiacos and Ethnikos

Consecutive championships

18 in a row 14 in a row 12 in a row 9 in a row 6 in a row 5 in a row 3 in a row 2 in a row

Appearances in A' Ethniki (1967―2024)

A' Ethniki (National Division) started in 1967, but the Greek championship started in 1923 as a Panhellenic Championship. The Hellenic Swimming Federation declares all championship winning teams as champions from 1928 and onwards. Teams in bold participate in the 2023–24 season.

Greek clubs in European competitions