H2o: Just Add Water features Claire Holt as Emma Gilbert, Phoebe Tonkin as Cleo Sertori, and Cariba Heine as Isabella ‘Bella’ Hartley (from season 2) as the three main mermaids in this Australian teen fantasy series.
Main cast
- Emma GilbertClaire Holt1–3Main
- Cleo SertoriPhoebe Tonkin1–3Main
- Isabella ‘Bella’ HartleyCariba Heine2–3Main
- Rikki ChadwickIndiana Evans3Main
Supporting cast
- Lewis McCartneyAngus McLaren1–3Supp
- NikkiCleo Massey1Supp
- Zane BennettBurgess Abernethy1–3Supp
- Charlotte WatsfordBritney Raymond2Supp
- Dr. Linda DenmanLara Cox1Supp
- NarelleAshleigh Brewer1Supp
Guest & voice
- TiffanyKirsty Lee Allan1Guest
- GraceAlyce Platt3Guest
No matches — try another name.
About this cast
H2o: Just Add Water is an Australian fantasy drama television series that first aired in 2006 on Network Ten. The show follows three teenage girls who, after a mysterious encounter on a moonlit beach, discover they turn into mermaids when they come into contact with water, each with unique hydrokinetic powers. The main cast includes Claire Holt, Phoebe Tonkin, and Cariba Heine (from season 2) as…
FAQs
Who plays Emma Gilbert in H2O: Just Add Water?
Claire Holt plays Emma Gilbert, one of the three original mermaids, for the entire series (seasons 1–3).
Who plays Rikki Chadwick in H2O: Just Add Water?
Indiana Evans plays Rikki Chadwick, who joins as the third mermaid in season 3 after Claire Holt’s departure.
How many seasons did H2O: Just Add Water have?
The series had three seasons, airing from 2006 to 2010.
Who plays Isabella ‘Bella’ Hartley in H2O: Just Add Water?
Cariba Heine plays Bella Hartley, who is introduced in season 2 as a replacement for one of the original mermaids.
Sources & where to watch: IMDb · Wikipedia · Where to watch (JustWatch UK) · Updated June 2026