Full episodes of "H2O : Just Add Water" are available at Hulu.com. The site has all 78 episodes of the show available for free streaming on computers. Viewers can stream the show to their televisions and mobile devices through the premium subscription service Hulu Plus.
"H20: Just Add Water" revolves around the lives of three friends who become mermaids with super powers after an encounter on a mysterious island. The show received positive ratings and ran for three seasons from 2006 to 2010.
The franchise also produced a movie of the same name in 2007 and spurned two spin-off series: "Mako: Island of Secrets" in July of 2013 and "H2O: Mermaid Adventures" on Netflix in 2015.