Every season of H2O: Mermaid Adventures ever, ranked from best to worst by thousands of votes from fans of the show. The best seasons of H2O: Mermaid Adventures!

Cleo, Emma and Rikki get stranded on Mako island and fall into a magic pool where their lives change forever.

The Secret of Mako Island

Emma competes in a contest, Cleo is stuck babysitting an intern and save an injured sea turtle.

Caught in the Net

The girls discover of an ancient mermaid statue and return it but treasure hunters have another idea.

The White Mermaid

A storm threatens to wash out a birthday party.

A Stormy Party

Zane's father plans a luxury resort on Mako Island.

Mako Island Hotel

The Mysterious Seaweed

Discarded plastic bags pose a threat to Teddy and his friends.

It's in the Bag!

Atmospheric disturbances result in disastrous consequences.

Dolphin City Triangle

Dolphin City is the location for a new movie.

Poseidon's Daughter

Danny gets captured by the Oceanic Center for observation.

Dolphin City Mascot

Lewis and the girls must find what's behind mysterious sound waves that are creating havoc.

Bad Waves

Berk breaks a tooth and wanders near the beach in pain, causing a panic.

Jaw-ache!

Rikki takes matters into her own hands by spying on her dad and his new girlfriend.

The Lost Ring

Reported Missing

Memory Lapsse

Valentine's Day

Kidnapped!

A Strange Phenomenon

Handle with Care

The Return of the White Mermaid

Three Days Underwater

Robot Duel

The Creature from the Bay

Underwater Takeover

Imminent Danger

Trapped

The lives of teenagers Emma, Cleo and Rikki are forever changed when a magical, forbidden island gives them the power to turn into mermaids.

The Best Seasons of H2O: Mermaid Adventures

The Best Seasons of H2O: Mermaid Adventures

Season 1

Season 2