Giyu and Shinobu Swap Uniforms for Hot Spring Yukata
The real draw is the art. ufotable, the studio behind the anime, has drawn the cast in hot spring yukata exclusively for this event, and the official pages show Tanjiro Kamado, Zenitsu Agatsuma, Kanao Tsuyuri, Giyu Tomioka, and Shinobu Kocho mid-soak. That art anchors an "onsen yukata ver." goods line: trading can badges, acrylic stands, acrylic keychains shaped like bathhouse locker keys, and items modeled on old-school milk bottle caps, a nod to the classic post-bath bottle of milk.
A second line uses illustrations of the characters enjoying Hakone Kowakien itself, printed on can badges, acrylic stands, face towels, and waterproof multi-use pouches. Every ¥2,000 spent on goods earns one of 10 bonus postcards at random, according to Japanese anime news site Anime Anime.
The collab drink pulls from series lore. In Demon Slayer, demons can't stand wisteria, and houses marked with the wisteria crest shelter Demon Slayer Corps members free of charge. The event's wisteria-flower drink is themed on that safe house, and each purchase comes with one of 15 random original tags.
Themed Baths at a Swimsuit-Friendly Spa Park
Hakone Kowakien Yunessun is an all-weather spa theme park in Hakone, the hot spring resort town southwest of Tokyo, where most of the bathing areas are swimsuit-friendly. That makes it an unusually good fit for an anime collab, since the event can build actual attractions rather than just a pop-up shop.
And it does. The official event page lists collab baths, a collab sauna, drinks, goods, special admission tickets, themed hotel rooms, and stay plans. The baths include one themed on the wisteria-crest house and another modeled on the Infinity Castle, the demons' stronghold from the current film trilogy. Collab tickets bundle a towel styled after the plain souvenir towels Japanese companies hand out as freebies, an in-joke that fits the series' Taisho-era setting.
Next door, Hakone Hotel Kowakien offers collab guest rooms with an exclusive gift for overnight guests, plus stay plans that include an original tenugui hand towel. An X follow-and-repost campaign runs alongside the event.
One Year to the Day After Infinity Castle Opened
The event opens July 18, 2026, exactly one year after Demon Slayer: Kimetsu no Yaiba Infinity Castle Chapter 1: Akaza's Return hit Japanese theaters. The film is the first of a trilogy adapting the manga's final battle between the Demon Slayer Corps and the demons inside the Infinity Castle. It was also the only Japanese title nominated in the animated film category at the 83rd Golden Globe Awards, though it went home without the prize.
The franchise it caps remains enormous. Koyoharu Gotouge's original manga ran 23 volumes through publisher Shueisha's Jump Comics imprint and has topped 220 million copies in circulation, while ufotable's anime adaptation has been running since the first TV series premiered in April 2019.
Looking Ahead
Kimetsu no Yaiba x Yunessun Hakone Onsen Tan Fuji no Hana no Kyusoku runs July 18 through October 4, 2026, at Hakone Kowakien Yunessun in Hakone, Kanagawa. It's a Japan-only event with no touring or international version announced, so for overseas fans this one is a summer-trip destination rather than an online drop.
There is a home-viewing consolation on the way: Infinity Castle Chapter 1 arrives on Blu-ray and DVD in Japan on July 29, 2026. The Demon Slayer TV series streams internationally on Crunchyroll and Netflix, and Viz Media publishes the manga in English.