The film's original planned title was Atlantis. However, it was decided to change the title to avoid confusion with Atlantis, der verlorene Kontinent (1961), so the title became 7 Cities of Atlantis. But then the TV series Der Mann aus Atlantis (1977) flopped, and executives did not want to associate the film with that show, so it became Warlords of the Deep. However, Columbia, who partly financed, thought this was too close to their recent hit Die Tiefe (1977), so the title was changed again to Warlords of Atlantis.
Lea Brodie receives an "introducing" credit. She previously was known as Lea Dregorn, under which name she had received an "introducing" credit for The Lifetaker (1975).
Peter Cushing originally was cast as Atraxon, but he was forced to withdraw from the role when Son of Hitler (1979) went over schedule.
The fourth action-fantasy collaboration between director Kevin Connor and actor Doug McClure. The first three were Caprona - Das vergessene Land (1974), Der sechste Kontinent (1976), and Caprona II (1977) which were made by Amicus Productions. Amicus folded in 1977, so Warlords was made by EMI Films and Columbia Pictures.
Filming started September 5, 1977. Location filming on Malta began on October 1, 1977. A large amount of footage was shot on the island of Gozo. Filming ended January 13, 1978.