H2O: Just Add Water, also known as H2O, is an Australian dramatic fantasy television programme for children and teenagers created by Jonathan M. Shiff. It first screened on Australia's Network Ten and runs in syndication on channels in over 120 countries and has a worldwide audience of more than 250 million. It was filmed on location at Sea World and other locations on the Gold Coast. The show's premise revolves around three teenage girls facing everyday teen problems with an added twist: they're mermaids with powers over water. The theme song "No Ordinary Girl" is performed by Ellie Henderson in series one, by Kate Alexa in series two and by Indiana Evans in series three.
Only two series with a total of 52 episodes were originally planned, but due to popular demand, a third and final series was filmed. Series one premiered in July 2006, followed by series two in September 2007. Series three first aired in the United Kingdom in October 2009, with the Australian premiere occurring in May 2010.