This article is about the first season of the H2O: Mermaid Adventures series. To view the first season of H2O: Just Add Water click here and to view the first season Mako: Island of Secrets click here.

The first season of H2O: Mermaid Adventures.


Image Title Original Airdate Episode
Cleo, Rikki and Emma in The Pond The Secret of Mako Island May 22, 2015 01 1.01
Cleo, Emma and Rikki get stranded on Mako Island and fall into a magic pool where their lives change forever.
MA-S1E2 Caught in the Net May 22, 2015 02 1.02
Emma competes in a contest, Cleo is stuck babysitting an intern and save an injured sea turtle.
MA-S1E3 The White Mermaid May 22, 2015 03 1.03
The girls discover of an ancient mermaid statue and return it but treasure hunters have another idea.
MA-S1E4 A Stormy Party May 22, 2015 04 1.04
A storm threatens to wash out a birthday party.
MA-S1E5 Mako Island Hotel May 22, 2015 05 1.05
Zane's father plans a luxury resort on Mako Island.
MA-S1E6 The Mysterious Seaweed May 22, 2015 06 1.06
Aggressive blue seaweed attacks Emma.
MA-S1E7 It's in the Bag! May 22, 2015 07 1.07
Discarded plastic bags pose a threat to Teddy and his friends.
MA-S1E8 Dolphin City Triangle May 22, 2015 08 1.08
Atmospheric disturbances result in disastrous consequences.
MA-S1E9 Poseidon's Daughter May 22, 2015 09 1.09
Dolphin City is the location for a new movie.
MA-S1E10 Dolphin City Mascot May 22, 2015 10 1.10
Danny gets captured by the Oceanic Center for observation.
MA-S1E11 Bad Waves May 22, 2015 11 1.11
Lewis and the girls must find what's behind mysterious sound waves that are creating havoc.
MA-S1E12 Jaws-ache! May 22, 2015 12 1.12
Burke breaks a tooth and wanders near the beach in pain, causing a panic.
MA-S1E13 The Lost Ring May 22, 2015 13 1.13
Rikki takes matters into her own hands by spying on her dad and his new girlfriend.
MA-S1E14 Reported Missing July 15, 2015 14 1.14
Clown fish begin to vanish, so the girls investigate why this is happening.
MA-S1E15 Memory Lapse July 15, 2015 15 1.15
Cleo forgets about her ability to change into a mermaid, so Emma and Rikki must make sure she doesn't transform in public.
MA-S1E16 Valentine's Day July 15, 2015 16 1.16
Lewis wants to share a big secret with Abby on Valentine's Day, and Cleo worries that he will tell her about the girls' mermaid identities.
MA-S1E17 Kidnapped! July 15, 2015 17 1.17
Bobby's twin brother gets abducted by someone in a curious speedboat.
MA-S1E18 A Strange Phenomenon July 15, 2015 18 1.18
Cleo has some powerful nightmares after her father goes to sea on a mission.
MA-S1E19 Handle With Care July 15, 2015 19 1.19
Tired of the racket Miriam and Zane are making at their beach party, Bernie leaves his cave -- giving the Vandals a chance to move right in.
MA-S1E20 The Return of the White Mermaid July 15, 2015 20 1.20
To protect the White Mermaid, the girls guide explorer Stanley Finch to the underwater Stone Circle, whose magic makes Stanley think he's a pirate.
MA-S1E21 Three Days Underwater July 15, 2015 21 1.21
When a spell forces Rikki to remain a mermaid until the next full moon, she has to find a way to lay low -- and underwater -- for three full days.
MA-S1E22 Robot Duel July 15, 2015 22 1.22
Lewis is thrilled when the university hosts an underwater robot competition, but the girls fret over the safety of their marine friends.
MA-S1E23 The Creature From The Bay July 15, 2015 23 1.23
Emma's younger brother catches a glimpse of her mermaid tail and thinks he's seen a sea monster -- soon the whole town is in an uproar.
MA-S1E24 Underwater Takeover July 15, 2015 24 1.24
The mermaids turn to a cranky giant octopus for help when the Vandals invade the bay with a horde of stinging jellyfish.
MA-S1E25 Imminent Danger July 15, 2015 25 1.25
Having played one too many practical jokes, Teddy can't get anyone to believe his warning that an underwater volcano is about to erupt.
MA-S1E26 Trapped July 15, 2015 26 1.26
Lewis joins a famous explorer in a high-tech submarine to hunt for a sunken treasure ship, but a mishap strands them at the bottom of the sea.
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