Only two series totaling 52 episodes were originally planned, but a third series was filmed due to popular demand.

The show was filmed on location at Sea World and other spots on the Gold Coast, Queensland, Australia.

German public broadcaster ZDF co-produced the series and distributes it globally.

The casting session held at Warner Bros. Movie World in August 2005 attracted close to 1000 teenage girls.

Associate producer Joanna Werner said the Gold Coast's natural landscape and soundscapes were essential to the show, arguing a mermaid series wouldn't work if produced in Melbourne.

Around AU$10 million was spent producing the initial 26-episode first season in 2005-2006.

The three lead actresses, Claire Holt, Phoebe Tonkin, and Cariba Heine, began training for their swimming skills with the mermaid tails five days a week starting in October 2005.

Claire Holt left the show after series two to film Messengers 2: The Scarecrow, with her character's exit written as traveling the world with her family.

Angus McLaren departed partway through series three to begin filming Packed to the Rafters, but returned as a guest star for the show's final episode.

Craig Horner did not return for series three because he was filming Legend of the Seeker.

The theme song 'No Ordinary Girl' was performed by a different singer in each series: Ellie Henderson in series one, Kate Alexa in series two, and Indiana Evans in series three.

The series spawned a spinoff, Mako: Island of Secrets, announced in July 2011, in which Cariba Heine makes a guest appearance as Rikki in the final season.