1 - 20 of 35 Works in Alternate Universe - H2O: Just Add Water Fusion
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In this world, we're all alone by Siempre_Es_La_Misma_Situacion
Fandoms: Voltron: Legendary Defender
03 Sep 2025
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Summary
Lance was the only merperson he’d ever known for as long as he could remember, which admittedly wasn’t that long but you got his point.
That was until a certain mullet head fell into his moonpool.
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Summary
Gaster investigates a mysterious phenomenon.
Series
- Part 2 of H2O: Just Add Undertale!
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Killer has heard of a pond that turns people into mermaids at midnight during a full moon. After setting out to prove it wrong, things go awry.
Note: The first 3-4 chapters or so were written a year ago, but they have such a unique soul to them that I'm not rewriting.Series
- Part 1 of H2O: Just Add Undertale!
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The Pull Of The Tide by ayalovesmoony
Fandoms: Harry Potter - J. K. Rowling, H2O: Just Add Water, Mako Mermaids
21 Jul 2025
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When young cousins Andromeda, Sirius, and Regulus wander into a mysterious pool deep inside a volcano during a full moon, they stumble into something magical, something that changes them forever. The next morning, they discover that touching water turns them into mermaids and a merman.
Ten years later, Sirius and Regulus escape their abusive family in England and return to Australia, where Andromeda welcomes them into her home. As they settle into a new school and a quieter life, they begin to notice something strange about a boy named James Potter, he's always avoiding water. Suspicious and curious, Sirius and Regulus begin to wonder: could James be like them?
Secrets, saltwater, and new beginnings await as the mystery unfolds.
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Timothy Jackson Drake-Wayne, has a huge secret. A secret he had hid with his life. A secret no one in even his family knew. The Waynes, for all their detective prowess, didn't even realise he was hiding one.
Tim is a merman.
A creature of the sea.
No one could know.
The Waynes, being humans, could never know Tim's secret. It was hard to keep, but.. when is it not?
Yet what happens when the Waynes take a spontaneous beach trip? One that might just make the water - sorry, no, secrets - overflow?
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Me, Under your Umbrella by aithere
Fandoms: 逆爱 | Revenged Love (TV), 逆袭 - 柴鸡蛋 | Counterattack - Chai Jidan, H2O: Just Add Water, Mako Mermaids
14 Jul 2025
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Jiang Xiaoshuai has one rule: don’t get wet.
Because when he does? Boom. Mermaid. Tail, scales, aquatic drama—the whole splashy package.He’s got it under control... until Guo Chengyu starts showing up with umbrellas, dumplings, and suspiciously specific questions like, “Hypothetically, how would a person who hates water wash their hair?”
As Xiaoshuai scrambles to hide his secret, he doesn’t realize one thing: Guo already knows.
Series
- Part 4 of Aithere's Revenged Love One-Shots
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To Keep or To Not Keep by McTom_the_Dimensional_Traveler
Fandoms: Rune Factory 4, Rune Factory (Video Games)
08 May 2025
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Summary
When the lies and secrets of being a mermaid become too much for Clorica to handle, she rethinks about her and her friends’ “No telling” rule in terms of her boyfriend.
Series
- Part 3 of executormctom's MerMay 2025 Fics
- Language:
- English
- Words:
- 3,765
- Chapters:
- 1/1
- Kudos:
- 1
- Hits:
- 43
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Scars guide to (failing to) catch a mermaid by Starlightzora for Lizzielied
Fandoms: Life Series | 3rd Life SMP Series
07 May 2025
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Summary
Scar drags cleo along to try find out about the mermaid she saw earlier that week. Little does she know cleo already knows about the mermaids
Oneshot based off my friends socmed "seaside conspiracies" <3
- Language:
- English
- Words:
- 2,918
- Chapters:
- 1/1
- Kudos:
- 3
- Hits:
- 93
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H2O: Just Add Lesbians by ayalovesmoony
Fandoms: Harry Potter - J. K. Rowling, H2O: Just Add Water
21 Apr 2025
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Summary
Lily Evans was terrified of water, her best friend Mary Macdonald adored it.
Marlene Mckinnon is a stoner chick who happens to befriend them.
One accidental night on Mako Island, their whole lives changed for the better. When the three of them inherit not only magical powers, but also mermaid tails whenever they come into contact with water, they have to keep it a secret from everybody. Which is hard when Lily's best friend is none other than James potter.
The Marauders and their significant others soon become suspicious of the girls and James, especially when a new girl with a twin already there moves into town exactly two years after all the weird behaviour began.
OR
H2O AU! Lily, Mary and Marlene are Cleo, Emma and Rikki but a surprise guest will make an appearance later on and add onto that list as a mermaid - along with an annoying bitch who I'm sure most H2O fans will be pissed to see.
James is basically Lewis - except he has nosy friends and the biggest fattest crush on his best friends brother.
Alternating POV's every chapter!
Slow updates atm!
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Summary
At long last, he relented.
“You must be a romantic or something.” He couldn’t help but chuckle a bit at the absurdity of the situation. “You’re so weird! Fine, you’ve got yourself a deal! But if you die out here, I swear I’ll come back as a ghost and haunt you! So don’t drown!”
“I don’t think you have any right to be saying that to me. See ya’, Korekishi!” He beamed at him with a small wave, before diving back under the waves like he was born to do it.
Eugene let out a long-suffering sigh, before realizing the time and rushing to get to class. He couldn’t be late for a second day in a row. If Mogari drowned, would that make him a murderer? Assisted suicide? Criminal negligence? He would have to find out tomorrow.
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Mogari is new in town and Eugene initially wants nothing to do with him after a bad first meeting. But eventually he grows on him (like mold) and he decides that getting some new friends might not be so bad. He had no way of knowing what this decision would lead to---and the way their lives would intertwine with both each other, and some other boys at their school. -
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you know the story of h2o: just add water? Where three girls jump into a pool on a full moon and gain tails? It's an amazing story, one I've loved since I was a kid!
SO! What if that story happened to Kiara Carrera? And how would it work in the obx universe?
"Kiara’s breath caught in her throat, panic surging through her veins. And when JJ finally looked up, his eyes landed on her.
To say his jaw dropped was an understatement.
“Kie?” he said, his voice cracking slightly. He took a step forward, his phone slipping from his fingers and hitting the floor with a soft thud. “What the hell is that?”"
Series
- Part 35 of Outer Banks
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Blue Is The Water (that beckons, that buries) by Pitchpine
Fandoms: The Magnus Archives (Podcast)
18 Jan 2025
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Jonathan Sims is a merperson who has always lived below the waves. One day, however, he steals away and ventures to the surface in search of someone he lost. On newfound legs, his search takes him to The Magnus Institute — the foremost academic institution researching crypto-zoology and crypto-marine biology, headed by the enigmatic Elias Bouchard. With his new position as Head Archivist, Jon is in the perfect place to continue his search. Hiding his secret identity as merfolk should no problem, either.
After all, it's not like he wants to be friends, much less more-than-friends with the humans.
And surely none of them are hiding secrets of their own.
Right?
...
In other words: It's a selkie and merfolk AU! Jon is merfolk, and goes to the surface in search of a long-lost friend. He takes a job at the Magnus Institute as part of his search, and soon finds himself embroiled in all kinds of drama — including, but not limited to, falling in love.
Complete!
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It's (Just) You and Me (Forever, Ever, Ever) by sn0w_quill
Fandoms: Death Note (Anime & Manga), H2O: Just Add Water
15 Oct 2024
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Summary
There he was, just sitting there and reading a book under the dim lit bookshelves. Like an asshole.
Light wasn't stalking someone or anything, thank you very much, just keeping an eye on this guy. The library was public school space anyways.
L Lawliet, Light's nemesis. A new kid that started this year.
L. What a strange, unconventional, annoying name. Suited him perfectly.
'Look at him,' Light huffed internally, derisive and contemptuous, 'reading all innocently. I should drown him in the ocean."
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16 year olds Light, Misa and L are living on the Golden Coast, Australia and get an upclose and personal adventure with the ocean after a group project gone wrong, all while having to deal with family and teenage troubles.
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Yaz is worried that her fam’s secret — that they turn into mermaids on contact with water — is in danger of being found out by the mysterious captain of a fishing boat called the Stenza. When she tries to deal with it on her own, things go sideways, and her fears may end up becoming true.
Series
- Part 5 of Deep Blue Underworld
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Harry Bahls and Fredrikki Chadbearintonwick by Daddy_Thatcher
Fandoms: Five Nights at Freddy's, Original Work, H2O: Just Add Water
24 Jul 2024
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- Language:
- English
- Words:
- 110
- Chapters:
- 1/1
- Hits:
- 20
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A taste of forever. As Eugene disappeared, the words echoed, reverberating around them.
- Language:
- English
- Words:
- 300
- Chapters:
- 1/1
- Kudos:
- 9
- Hits:
- 113
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After falling into a mysterious pool on his annual camping trip to Mako Island, Merlin's world is turned upside down when he suddenly finds himself growing a tail every time he touches water. To make matters worse, he's slowly falling for his prattish classmate Arthur Pendragon, who can sense Merlin is hiding something from him.
With help from his two best friends, Merlin attempts to navigate his newfound powers and uncover the secrets of Mako, all while hiding his secret and facing the danger of being discovered.
Or: The H2O: Just Add Water/Mako Mermaids AU no one asked for
Series
- Part 1 of Mako Merlin
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I'm from the deep blue underworld by Coolish_Corvid_Cryptid
Fandoms: Dream SMP, H2O: Just Add Water, Minecraft (Video Game)
07 Jul 2024
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He takes a deep breath and takes Tubbo's outstretched hand. He slides forward and for a terrifying moment he’s submerged. Submerged in the surprisingly warm pool. But then Tubbo and Tommy are keeping him afloat. He gasps for air and clings to them desperately.
Then something strange happens. The water starts bubbling around them. Tiny droplets float out of the water, sparkling as they float toward the moon. The moon, directly overhead, shining down at them. He can’t do anything but stare, enchanted by the pool.
Then all at once, it's over. He glances at his two classmates and they glance back.
“What the fuck?"
Bench trio H2O AUTommy, Tubbo and Ranboo become mermaids when they touch water, shenanigans ensue
Background sleepy bois
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Fish me out of the gutter by Cosmisa
Fandoms: The Legend of Zelda: Breath of the Wild/Tears of the Kingdom
20 May 2024
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On a regular quest, Link finds a strange cave with glowing water. However, he gets a little more than he bargained for when the magical grotto gives him some magic of his own.
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It’s a wedding! Joy Smith’s cousins, John and Donna, are visiting for Donna’s wedding. The fam is invited and excited to have a good time, but comments from Cousin John about the full moon have Joy a little worried for what could happen.
Series
- Part 4 of Deep Blue Underworld
- Language:
- English
- Words:
- 2,802
- Chapters:
- 1/1
- Kudos:
- 9
- Hits:
- 121