It recently came to my attention that there exists, in Japan, an annual Tokyo International Shark Film Festival. Even as an enjoyer of the sharksploitation subgenre of action, horror, and action horror that includes Jaws, Deep Blue Sea, and all the way up to the recent Dangerous Animals, it was (and remains) surprising to me that there was enough shark horror output to sustain an entire film festival. But it exists! The way I came about this knowledge was through the press notes of the most recent winner of the Audience Award at the Festival, Morihito Inoue’s Onsen Shark or Hot Spring Shark Attack. Inoue’s debut has many of the vibes of the terminally unserious Sharknado films, but feels somewhat less like it’s poking fun at our finned friends or me for watching it. It’s a self-aware but earnest-feeling outing that could be one of the secret joys of 2025.
In Onsen Shark, bodies have begun appearing on the shores of the seaside resort town of Atsumi, which is known for its spas and luxury resorts. The bodies have signs of shark attacks and that is no bueno for the town and its mayor Mangan (Takuya Fujimura) who are trying to get a posh multi-storey spa and resort off the ground. If you know, you know, and there are a boatload of similarities and easter eggs to be found between Onsen Shark and the classic Jaws (1975) but I think it’s safe to say that Inoue imbues his take with it’s own special flavour and feel.
A marine researcher is the latest to wash up on the beach, and one of his fellow scientists, Dr Kose (Yuu Nakanishi) steps in to continue his investigation. It turns out that these aren’t ordinary sharks but an ancient species called Carcharodon fons callidus on whose bones the new resort is being built. This has caused these sharks to reemerge, malleable skeletons and all. This absurd trait is how they’re able to squish themselves into the pipes of the spa’s onsens or hot spring baths and munch on their prey.
At the same time, a mysterious and jacked-as-hell Onsen Guardian named Macho (Sumiya Shiina) appears to face down the threat of the sharks. Even with the benefit of at least one flashback and some exposition, I found myself with more questions than answers about Macho, his origins, and his intent. What is not in question is his diet and training regimen, which is unquestionably rigorous.
Macho, Dr. Kose, and Mayor Mangan join forces to take out the sharks and defend Atsumi, and I’ll be darned if they aren’t my favourite team-up since the spiritualists in Exhuma (2024). The trio has such a natural chemistry and a perfect complement of skills and personalities that it almost – almost – makes me want to root for them over the sharks. Not quite though because while charming, the heroic trio cannot hold a candle to the charm of the sharks themselves. These sharks are rendered cheaply but lovingly with some combination of toys and fairly rudimentary by 2025 standards animation. And when they scream, whether in terror or with a kind of maniacal glee, they exposit only the word “shaaaaaaaaaaaaaark!” What could be more adorable?
Well, a thorough scientific explanation of the sharks’ biology, origin, and potential weaknesses might be more adorable, and Inoue is happy to oblige. Sometimes, a film will go so far in its explanation that it leaves too little to the imagination and invites me to look for holes in that explanation (ahem). But Onsen Shark, even as it revels in the inherent silliness of sharks that can collapse their bones and squeeze into the drain of a hot tub to feast on spa-goers, is eager to face this possibility head-on. We’ll see animated simulations of shark behaviour and a plan of attack for our trio of heroes to vanquish the threat from their trusty yellow submarine, the Orca.
One could simply write off Onsen Shark as a parody of Jaws. It is extremely clear that Inoue is both aware and in love with that seminal shark tale, but he’s not out here to poke fun at it. Instead, and even though Onsen Shark is quite firmly lodged in b-movie territory, Inoue has a certain reverence for both it’s many-toothed antagonists and it’s audience that is often lacking in other sharksploitation outings. After my experience with Onsen Shark, there’s no question in my mind that it’s deserving of its accolades, and will be a delightful experience if you can catch it in it’s theatrical run. It’s fun, but the kind of gleeful and chaotic fun that feels appropriately meaty.
Onsen Shark/Hot Spring Shark Attack begins its limited theatrical run on July 11, 2025 from Utopia. A list of screening locations can be found at the official website for the film here.
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