“The Mromi-san of the Waveline” — A Short Comedy of Mermaids, Myth, and Hakata Dialect

Muromi-san on the Shore (The Mromi-san of the Waveline) is a slightly unusual slice-of-life comedy anime, based on the manga by Keiji Najima. It was adapted into an anime in 2013.

The appeal of this series lies in the laid-back and surreal daily life of Muromi-san and the unique sea creatures (such as mermaids, kappas, and even krakens!) who gather around her. The show also touches on social issues like fishing and environmental problems, while keeping the tone lighthearted with plenty of humor. Muromi-san’s “disappointingly cute” personality and her lively interactions with her eccentric friends make for a series that is sure to bring a smile to your face!

“You can meet her in spring, yo—.”
One day, Takurō Mukōjima, a high school student who loves fishing, reels in an incredible catch: a twin-tailed mermaid girl named Muromi-san.

This gag manga, serialized in Weekly Shonen Magazine to great popularity, has been given an anime adaptation! Yui Tamura, a Fukuoka native, plays the Hakata-dialect-speaking Muromi-san, while Ai Nonaka, also from Fukuoka, voices Hi-chan, and Mai Nakahara from Kitakyushu takes on the role of Levia-san from Kokura. The supporting cast is packed with carefully chosen voices.

The anime is produced by Tatsunoko Production—well known for Sket Dance—teaming up with rising young director Tatsuya Yoshihara. Character design is handled by Kikuko Sadakata (Princess Resurrection).

Adding even more appeal, the opening theme song “Your Sea from the Seven Seas” (Nanatsu no Umi yori Kimi no Umi), sung by Sumire Uesaka—who also voices Muromi-san’s best friend, Miss Sumida—is a highlight in itself.

Muromi-san, Mount Fuji, the Yeti, and even Herbie run amok in this over-the-top comedy of interspecies interactions!

Watching The Mromi-san of the Waveline feels like stepping back into the 90s. The round cheeks, flashy eyelashes, and bright hair colors evoke that era of afternoon anime, while the constant stream of Hakata-dialect lines adds a homely, friendly vibe.

At just 15 minutes per episode, the show packs myths, gags, and bizarre characters into a fast-paced format that leaves you both laughing and wanting more.

The heroine, Muromi, is a mermaid accidentally caught by a boy named Takurō. She’s a boozy, talkative, larger-than-life character who casually drops stories about shaping Earth’s history. But behind her flashy looks lies a mix of pure-hearted vulnerability and brash delinquent energy.

Sometimes she shows a romantic, even sentimental side; other times she rants about an ancient whale ex-boyfriend like a true delinquent. She refuses help when hurt, yet never abandons her friends. That balance of toughness and warmth makes her impossible to dislike. And her Hakata dialect gives every line a rhythm and charm that makes her feel alive.

At around 15 minutes per episode, Muromi-san hits a sweet spot. Too short to drag, but long enough to deliver punchy gags, mythological parodies, and even the occasional heartfelt moment.

From jellyfish with muffled, absurd voices to cicadas chatting idly on the street, every living creature is given personality. Episodes like the coelacanth trauma arc or the oarfish employment gag blend silliness with surprising poignancy. The pacing ensures that the humor never overstays its welcome, while the emotional beats land just enough to make you care.

Despite its short runtime, the show boasts an impressive voice cast. Yui Horie, Yukari Tamura, and others deliver sharp performances, with Tamura’s Muromi standing out. She nails everything from drunken banter to heartfelt moments, making Muromi a character both ridiculous and endearing.

And then there’s the OP. With its iconic “Muromiiii!” shout, it’s absurd, catchy, and perfectly matched to the show’s chaotic energy. You’ll find yourself watching it every time instead of skipping ahead.

The supporting cast is just as colorful: Leviathan, Yetis, kappas, aliens—you name it. Human characters are rare, making the series a festival of mythical and supernatural oddballs, all bouncing off Muromi in hilarious ways.

The Mromi-san of the Waveline isn’t for everyone. Some viewers will find it too strange, too niche. But for those who click with its blend of dialect humor, mythological gags, and short-form pacing, it’s a hidden gem.

The combination of Hakata-accent comedy, addictive OP theme, and 15-minute energy makes it unlike any other anime. It’s silly, nostalgic, and unexpectedly heartwarming.

If you’re looking for a short comedy that’s both bizarre and charming, let Muromi and her gang of misfit creatures take you on a seaside ride—you might just find yourself hooked.

• Muromi : Voiced by Yukari Tamura
• Takurō Mukōjima : Voiced by Daisuke Mizushima
• Hi-chan : Voiced by Ai Nonaka
• Miss Sumida : Voiced by Sumire Uesaka
• Miss Fuji : Voiced by Hitomi Harada

• Original Creator / Keiji Najima
• Director / Tatsuya Yoshihara
• Series Composition / Kazuyuki Fudeyasu
• Character Design / Kikuko Sadakata
• Animation Production / Tatsunoko Production

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