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This is the list of appearances & characters of H2O: Just Add Water!


Main Characters

Emma Gilbert

Character Actress Season One Season Two Season Three First Appearance
Emma Gilbert Claire Holt 26 episodes 25 episodes 0 episodes "Metamorphosis"

She first became a mermaid in Mako islands moon pool but only found out the next morning while swimming at the beach. She has the ability to freeze any object or object containing water and in the second season, under the power of a full moon aligned with various planets, she develops the ability to control ice and snow and, with help from Rikki and Cleo, has the power to summon a hurricane like storm. Emma and Rikki have their fair share of fights but always work things out with Cleo's help. Emma finds the first one of the lockets the girl's wear, Gracie's locket, but after a close call at slumber party where Miriam attempts to steal the locket Emma gives it to Cleo to keep it safe. She then recieves the third locket, Louise's locket, as gift from Ms Chatham who believes the lockets should be kept together. Emma can be a perfectionist and is a former competitive swimmer. She liked Byron in the first season but eventually Byron moves away and Ash moves in as the new supervisor of The JuiceNet Café with Emma's suggestion for a new supervisor. She was hoping to get the job herself and implied this to Wilfred but he didn't get the message. Emma and Ash finaly develope a relationship and on the season 2 finale Emma reveals her secret of being a mermaid to Ash. In season three Emma leaves town to go on a world round trip with her family and a new mermaid named Bella is introduced.

Rikki Chadwick

Character Actress Season One Season Two Season Three First Appearance
Rikki Chadwick Cariba Heine 26 episodes 26 episodes 26 episodes "Metamorphosis"

She first became a mermaid at Mako islands moon pool but first found out when she was hit by water from the park sprinkler system the next morning. Rikki was the last to discover her powers. Rikki is able to boil water or anything containing water, and in the second season she also developes the ability to control fire and lightning. Her parents are divorced and she lives with her father in a trailer. She is the rebellious new girl and a self-confessed loner who finds an attraction in the local bad boy, Zane Bennet. In the first season, under control of the full moon, her power grew to setting anything she touched on fire. While under the influence of the moon, Rikki kissed Zane on Mako Island, after Zane found her, but she accidentally burns him and he falls unconscious from dehydration . The next day in The JuiceNet Café, Zane appears, red after being burnt, and makes a comment about their kiss, but Rikki doesn't remember as her memory of that night disappeared when the full moon set. They first fall in love when trapped on a balcony together after Rikki helps Zane confront his fear of heights. They began to date in the middle of the first season and while walking with Zane, Rikki sees the second matching locket, Julia's locket, and rushes into the store in hoping to buy it but it was too expesive. Rikki's sudden interest in the locket promts Zane to want to buy it for her as a gift but before either of them get the chance Miriam bought it first. Miriam is jealous of Zane and Rikki's relationship because she still has feelings for Zane who she briefly dated. Zane then attempts to buy it from her but Miriam refuses to part with the necklace. Miriam then reveals her true intentions behind buying the necklace when she tells Zane she'd be willing to trade the necklace for a kiss. Zane kisses Miriam unaware that Rikki is standing behind him. When he turns around he quickly tries to explain but Rikki is hurt by his betrayal so he begs her to wait for him inside while he got the locket from Miriam. But after being rejected Miriam throws the locket into the sea claiming she never said she'd give him the locket just that she'd part with it and storms off. Zane then proves his feelings for Rikki by diving into the sea and getting the locket for her. However they find they have too many differences at the end of series 1 and break up but their relationship is rekindled in series 2 and permantly broken in series 3.

Cleo Setori

Character Actress Season One Season Two Season Three First Appearance
Cleo Sertori Phoebe Tonkin 26 episodes 26 episodes 26 episodes "Metamorphosis"

She first became a mermaid at Mako island moon pool and discovered she was a mermaid when she took a bath. Cleo has the power to levitate water and mould it into any shape as well as being able to control and manipulate it. She is awkward but a loyal friend. She is in love with Lewis but becomes jealous of a Marine Biologist named Dr.Denman when Lewis starts to work for her and appeares to have a crush on her . Late in season 1 Cleo and Lewis develope a relationship but new problems in her life lead to them to breaking up at the beginning of season 2. A new girl named Charlotte arrives, who is Cleo's friend at first but then Charlotte becomes jealous of Cleo's relationship with Lewis so Charlotte constantly tries to be with him. Charlotte and Lewis form a relationship, much to Cleo's dismay. Charlotte causes many problems for Cleo in season two, such as stealing her boyfriend and stealing her locket. Charlotte and Cleo soon become enemies and after Lewis had enough of Charlotte's actions, he breaks up with her and rescues Cleo from sharks. After he saves Cleo from a shark reef, they admit their feelings for each other and renew their romance.

Isabella "Bella" Hartley

Character Actress Season One Season Two Season Three First Appearance
Isabella "Bella" Hartley Indiana Evans 0 episodes 0 episodes 26 episodes "The Awakening"

Bella is "the new girl in town". She became a mermaid in the Sea Caves of Ireland when she was nine. Bella is a singer and provides a musical element to the show, occasionally shown singing with Nate's Band in the café. Her mermaid power is threefold: she can change water into gelatin, and then change that into a crystalline substance and explode water or jelly. If she loses focus on her power, the jelly or crystal will turn back into water, but she can also control this affect according to her will. She seems to show an interest in Will but is warned by Rikki to stay away from him for fear that he will discover their mermaid secret. She ignores this advise, resulting in Will getting her hand wet and finding out anyway. Bella convinces him that she is the only mermaid, but when Will helps the girls after Rikki is kidnapped, he learns the truth. Bella becomes angered when she figures out that Will only likes her because she is a mermaid, and tells him to stay away. Later on though, he assures her that he likes her for her, not just her mermaid abilities.

Main Supporting Characters


Lewis McCartney

Character Actor Season One Season Two Season Three First Appearance Return Appearance
Lewis McCartney Angus McLaren 26 episodes 26 episodes 14 episodes
(1-13 & 26)
"Metamorphosis" "Graduation"
(Last Episode)

Lewis has been Cleo's friend since they were five, and following the girls' transformation, also becomes friends with Rikki and Emma. He is academically gifted, thinks of himself as a scientist and has a passion for fishing. He discovers the girls' secret early on in the series and becomes determined to find the cause. He is in love with Cleo, which is later revealed to be reciprocated, and the two form a relationship late in series one. After the happenings of the first full moon of series two, Cleo breaks up with Lewis. They stay friends but remain a little embarrassed. Lewis develops a friendship with Charlotte, the new girl, who has a crush on Lewis and becomes his girlfriend after he finally gives up the thought that Cleo still cares about him. At the end of series two, Lewis suddenly dumps Charlotte because of her behavior towards the other girls, mostly Cleo. After he saves Cleo from a shark reef, they get back together.

Charlotte Watsford

Character Actress Season One Season Two Season Three First Appearance
Charlotte Watsford Brittany Byrnes 0 episodes 24 episodes 0 episodes "Fire and Ice"

Charlotte is the new girl in series 2 and is the girls' rival. She enjoys various forms of art, appreciates the sciences and becomes Lewis's girlfriend after Cleo leaves him. She hates Cleo as well as Rikki and Emma who hate her back, a dislike made even stronger after she becomes the fourth mermaid late in series two, armed with the powers of all three girls. Charlotte is eventually revealed to be the grandaughter of Gracie, one of the original three mermaids who 50 years earlier gave her powers up to the 50 year full moon. In the end of series two she becomes increasingly jealous of Cleo and asks Lewis to stop talking to the other girls, out of this Cleo feels abandoned and alone and runs away which leads to Lewis dumping Charlotte and returning to Cleo. Charlotte gets revenge by planning Emma, Rikki and most of all Cleo to lose their tails and powers, so Lewis would only care for her, but in the end she is the one who loses her mermaid tail and powers.

Zane Bennett

Character Actor Season One Season Two Season Three First Appearance
Zane Bennett Burgess Abernethy 20 episodes 7 episodes 26 episodes "Metamorphosis"

Zane is the local bad boy, and seems to think that he can get away with anything because his dad is rich. He appears to be arrogant, but has been seen to have a softer side. He desperately wants to impress his father, local land developer Harrison Bennett, who is more arrogant. Zane is an excellent swimmer. After becoming trapped on a sinking boat, he is rescued by Emma, and sees the end of her tail before she is able to slip away. Because of this, Zane becomes obsessed with finding the "sea monster". Later on in series 1 Zane and Rikki develop feelings towards each other to the disappointment of Miriam who assumed that she was with Zane. This happens when Rikki and Zane get locked up on a balcony together. While they later break up due to being "too different" from each other, they rekindle their relationship in series two after Zane discovers the girls are still mermaids. Zane becomes more of a supporting boyfriend in series 2.

Louise Chatham

Character Actress Season One Season Two Season Three First Appearance
Louise Chatham Christine Amor 9 episodes 0 episodes 0 episodes "Party Girls"

Louise Chatham is a mysterious elderly woman whom Cleo meets while working at the Marine Park. She hints to Cleo that she knows the girls secret and warns them about the effects of the full moon. Later, her boat is declared unseaworthy and Emma invites her to stay at her place. However, Miss Chatham sneaks out at night and sails off with her boat. After an altercation on the boat with Zane, she suffers a heart attack and is taken to a hospital by Lewis. Before going to a retirement residential home, she reveals to the girls that she once was a mermaid too, but that "the burden became too great, so she had to give it up", hinting that there is a way to give up their powers.

Supporting Characters

Byron Jade

Character Actor Season One Season Two Season Three First Appearance
Byron Jade Christopher Poree 8 episodes 0 episodes 0 episodes "Pool Party"

Byron is a swimmer and the love interest of Emma during series one. While under the effects of a full moon, Emma kisses Byron, almost leading to him finding out her secret. He asks Emma to train him to beat Zane, however, they kiss, and then have an argument as he calls her a 'heavy training dragon'.

Miriam Kent

Character Actress Season One Season Two Season Three First Appearance
Miriam Kent Annabelle Stephenson 10 episodes 0 episodes 0 episodes "Pool Party"

Miriam is the girls' rival in series one. She thinks of herself as the princess of town. Later in the series when Miriam finds out about Zane and Rikki's relationship she feels jealousy towards Rikki. She tries to win Zane back but her actions lead him to like Rikki more while liking her less. Also, while Emma was under the effects of the full moon, her and Zane's lips were frozen together, preventing them from leaving each other's feelings...literally.

Kim Sertori

Character Actress Season One Season Two Season Three First Appearance
Kim Sertori Cleo Massey 10 episodes 11 episodes 26 episodes "Metamorphosis"

Kim is Cleo's younger sister who is often bratty and gets Cleo into trouble thus causing a problem. At one point Kim finds Cleo's diary and nearly finds out Cleo's mermaid secret and tries to expose her. Cleo and the girls find a way to say that Miriam is the mythilogical creature.

Elliot Gilbert

Character Actor Season One Season Two Season Three First Appearance
Elliot Gilbert Trent Sullivan 6 episodes 4 episodes 0 episodes "Something Fishy"

Elliot is Emma's little brother. The two are very close and Emma makes many references to the fact that they have never had any secrets between them. After being saved from drowning by Rikki, Elliot develops a crush on her, though she is quick to reject his feelings.


Character Actor Season One Season Two Seaosn Three First Appearance
Wilfred Ariu Lang Sio 10 episodes 5 episodes 26 episodes "Pool Party"

Wilfred is the owner of JuiceNet. Emma also works at the JuiceNet, so he is also Emma's boss. When he is away, he usually leaves Emma in charge of the juice bar.

Dr. Linda Denman

Character Actress Season One Season Two Season Three First Appearance
Dr. Linda Denman Lara Cox 3 episodes 0 episodes 0 episodes "A Denman Affair"

Dr. Denman is a Marine Biologist who finds one of Cleo's mermaid scales that Lewis left behind. She tries to get Lewis to tell her where he found the samples, however, he refuses to reveal the source. In the end, she asks Lewis to travel with her for her work, but he decides to stay with Emma, Cleo, and Rikki. In the series one finale, she returns and sets up underwater cameras around Mako Island, eventually discovering the girls' mermaid secret. But in the end, she believed they lost their powers after going into the Moon Pool during a lunar eclipse. Though in truth, they only lost their powers for 12 hours.

Ash Dove

Character Actor Season One Season Two Season Three First Appearance
Ash Dove Craig Horner 0 episodes 10 episodes 0 episodes "Riding for a Fall"

Ash is the supervisor of JuiceNet (during series 2) due to Emma's disappointment at first (Emma wanted the job). Ash is a keen horse rider, and has worked as a riding coach. He and Emma formed a relationship and have gone out on a few dates. In the episode 'Moonstruck' of season 2, Emma was affected by the full moon (with Cleo and Rikki) and almost revealed her secret by calling him into the bathroom when she was wet with a tail. Luckily, Lewis steps in and stops him. During the series two finale, Emma reveals that she is a mermaid to Ash, and he is so stunned that all he has to say is "Cool". In the beginning Ash likes to wind up Emma because he discovers that when he does this Emma feels more attracted to him. Ash also has a falling out with Zane in the Juicenet causing the girl's group to split.

Max Hamilton

Character Actor Season One Season Two Season Three First Appearance
Max Hamilton Martin Vaughan 0 episodes 4 episodes 0 episodes "The Gracie Code"

An elderly man (and scientist), he was a friend of the original mermaids. His first appearance was in "The Gracie Code" when Lewis discovers his old research that he conducted on Mako Island. He reveals that he truly loved Gracie like Lewis truly loves Cleo and that he created the three lockets that the girls wear for the three original mermaids. He gives Lewis all his old research and pictures of the original mermaids. He knows that Cleo and Lewis are meant for each other so he gives Lewis hints about it. Lewis ignores him because he was dating Charlotte, but understands him when Cleo went missing and noticed how much he cared for her. He told Charlotte about mermaids when he realized that she was Gracie's granddaughter. He also revealed that the 50 year moon lines up with all the planets and will possess enough power to take away a mermaid's powers forever with no chance of ever regaining them back (probably because of his experience with Gracie).

Bev Sertori

Character Actress Season One Season Two Season Three First Appearance
Bev Sertori Deboarah Coulls 7 episodes 0 episodes 0 episodes "Catch of a Day"

Cleo's mother. She's a teacher. In episodes "Something Fishy" and "Under the Weather" she accidentally covers Cleo in water and turns her into a mermaid. In season 2, she divorced and makes Don, Kim, and most of all, Cleo worried.

Don Sertori

Character Actor Season One Season Two Season Three First Appearance
Don Sertori Alan David Lee 10 episodes 13 episodes 26 episodes "Catch of a Day"

Cleo's father. He is a local fisherman. He dislikes boys being around Cleo, except Lewis. In Season 2, he tries to make Cleo and Kim behave better. He makes for Cleo the childish birthday parties and doesn't understand that Cleo isn't a little girl. He became worried when his wife left him in season 2.

Lisa Gilbert

Character Actress Season One Season Two Season Three First Appearance
Lisa Gilbert Caroline Kennison 13 episodes 3 episodes 0 episodes "Pool Party"

Emma's mother. She was a lifeguard. She becomes worried after Emma left the swimming team. She also saved Harrison Bennet's (Zane's dad's) life when he almost drowned when she was younger.

Neil Gilbert

Character Actor Season One Season Two Season Three First Appearance
Neil Gilbert Jared Robinson 9 episodes 2 episodes 0 episodes "Pool Party"

Emma's father. He's one of Zane's father's workers. He is also worried after Emma left the swimming team.

Terry Chadwick

Character Actor Season One Season Two Season Three First Appearance
Terry Chadwick Andy McPhee 0 episodes 2 episodes 0 episodes "Wrong Side of the Tracks"

Rikki's father. He divorced with his wife. He lives with Rikki at the trailer park as revealed in the episode "Wrong Side of the Tracks". He likes Zane, but at first he hated him after Nate blames him for stealing the badge from his motorbike.


Character Actress Season One Season Two Season Three First Appearance
Tiffany Alice Hunter 7 episodes 0 episodes 0 episodes "Pool Party"

Miriam's best friend. She loves Lewis just like Cleo but backs off when Cleo and Lewis are together.


Character Actor Season One Season Two Season Three First Appearance
Nate Jamie Timony 11 episodes 8 episodes 26 episodes "Pool Party"

Zane's friend. He has lovesick on Cleo even though Cleo has turned him away on numerous occasions. In Season 2 he has the girls besotted over him when he puts on a special perfume that Zane found on the internet but then lost.

Harrison Bennett

Character Actor Season One Season Two Season Three First Appearance
Harrison Bennett Joss McWilliam 7 episodes 0 episodes 0 episodes "Moon Spell"

Zane's father. He's very angry at his son as he wants Zane to follow in his footsteps and become a successful business man. However Zane is too besotted with Rikki to listen to his father. During the end of Season 1, he finally starts being more happy for his son.

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