A global export hit
Co-produced with ZDF and distributed worldwide, the series reached audiences far beyond Australia and ran longer than originally planned.
H2O: Just Add Water is an Australian teen fantasy series that became a global phenomenon in the late 2000s. When Cleo, Emma, and Rikki get stranded on Mako Island during a full moon, a dip in a volcanic pool changes everything — ten seconds after touching water, they grow tails and discover elemental powers over the sea. With help from Cleo's friend Lewis, the trio juggles high school, crushes, and rivalries while keeping the biggest secret on the Gold Coast.
At a Glance
Full titleH2O: Just Add Water
CountryAustralia
LanguageEnglish
CreatorsJonathan M. Shiff
Co-producerZDF (Germany)
Theme song"No Ordinary Girl"
FilmingGold Coast, Queensland
Original networkNetwork Ten
Final episodeApr 2010
Why H2O still holds up
Dismissed by some as a kids' show about tails and teen drama, H2O built a worldwide fanbase that outlasted its original run — and launched several major careers.
H2O: Just Add Water arrived when teen fantasy was dominated by American sitcoms and British imports. An Australian production co-funded by German broadcaster ZDF, it looked like a niche experiment. Instead it ran for 78 episodes across three seasons, aired in more than 120 countries, and spawned the spin-off Mako: Island of Secrets.
What keeps people watching is the balance between spectacle and sincerity. The mermaid transformations are the hook, but the show invests in friendship — Cleo's anxiety, Rikki's independence, Emma's perfectionism — in ways that feel grounded even when the plot turns wild. Lewis McCartney is one of the best boy-sidekick characters in teen TV: smart, loyal, and never reduced to comic relief.
Then there is the cast. Phoebe Tonkin, Cariba Heine, and Claire Holt were unknown teenagers when the series began; within a few years Holt and Tonkin were anchoring The Vampire Diaries universe, and Indiana Evans was already a seasoned Disney Channel alum when she joined as Bella. For a generation that grew up on after-school reruns and DVD box sets, H2O is pure comfort viewing — and it earns that nostalgia honestly.
It turned a simple what-if — what if water changed you? — into one of the most exported Australian series of its generation.
Friendship over formula
The mermaid premise is flashy, but the core is three girls learning to trust each other — and that emotional through-line still works.
Lewis as the secret weapon
Angus McLaren's Lewis gives the show its heart and its humor, grounding the fantasy in someone who reacts like a real teenager would.
Launched careers that lasted
Phoebe Tonkin, Claire Holt, and Indiana Evans all parlayed H2O into years of film and television work on both sides of the Pacific.
Story
From a moonlit island pool to life as a secret mermaid
01
The Mako Island transformation
Cleo, Emma, and Rikki never planned to visit Mako Island — but a full moon, a volcanic pool, and ten seconds in the water change everything. The girls discover tails, powers, and a secret that could upend their ordinary teenage lives on the Gold Coast.
02
Three powers, one secret
Cleo controls water, Emma freezes it, and Rikki boils it — but keeping mermaid life hidden from school, family, and Zane is harder than any power. Lewis documents everything in his notebook while the girls learn to trust each other through every splash and close call.
03
New tides in season three
When Emma leaves and Bella Hartley arrives with powers of her own, the trio reshapes again. Will Benjamin, a diver drawn to Mako, and the lingering mystery of the island push the mermaids toward their final adventures — and the hardest choices about who gets to know the truth.
Cast
Main characters and performers
Behind the Scenes
Originally planned for two seasons and 52 episodes; a third season was added after strong global ratings.
Co-produced by Australian Jonathan M. Shiff Productions and German public broadcaster ZDF.
Filmed primarily on the Gold Coast in Queensland, with Mako Island scenes shot on location.
Spin-off series Mako: Island of Secrets premiered in 2013, set in the same universe.
Phoebe Tonkin and Claire Holt later starred in The Originals and The Vampire Diaries franchise.
Theme song "No Ordinary Girl" became synonymous with the show across multiple international broadcasts.
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FAQ
How many seasons of H2O: Just Add Water are there?
Three seasons with 78 episodes total, airing from 2006 to 2010.
Is H2O: Just Add Water based on a book?
No. It is an original series created by Jonathan M. Shiff for Network Ten, with ZDF as international co-producer.
What happens on Mako Island?
During a full moon, Cleo, Emma, and Rikki fall into a pool beneath a volcano on Mako Island and become mermaids with elemental water powers.
Is there a spin-off of H2O?
Yes. Mako: Island of Secrets is a spin-off set in the same universe, focusing on a new group of mermaids on Mako Island.
Who plays the mermaids in H2O?
Phoebe Tonkin plays Cleo, Cariba Heine plays Rikki, and Claire Holt plays Emma. Indiana Evans joins as Bella in season three.
Where was H2O: Just Add Water filmed?
Primarily on the Gold Coast in Queensland, Australia, with coastal and island locations used for Mako scenes.
Where can I watch H2O: Just Add Water?
Availability varies by region. Check MovieLinks for current streaming options, trailers, and related titles.
