Chiikawa Movie Announced: “The Secret of Mermaid Island” Brings the Siren Arc to Theaters in 2026

Fans of Chiikawa have reason to celebrate: the beloved mascot manga is getting its first-ever theatrical film. Titled Eiga Chiikawa: Ningyo no Shima no Himitsu (Chiikawa the Movie: The Secret of Mermaid Island), it’s slated for release in summer 2026. The film adapts the popular “Siren Arc,” following Chiikawa, Hachiware, and Usagi on a magical island adventure. 

Story & Source Material

The movie is based on a long-running arc of Chiikawa originally posted by creator Nagano on X (formerly Twitter) from March to November 2023.

This arc is known among fans as the “Siren Arc” (セイレーン編), or more simply the “island arc,” and marks one of the most ambitious and emotionally resonant stories in the series.

According to reports, the plot begins when Chiikawa, Hachiware, and Usagi receive a mysterious flyer inviting them to a “special island.” The flyer promises amazing rewards, such as “100× the usual reward for easy quests” and “limited island-only ramen and sweets, everything practically free.” Intrigued, the trio — along with their more cautious friend, Rakko-sensei — boards a boat and makes landfall on the island. But what seems like an innocent adventure hides unexpected challenges and mysteries.

Creative Team

One of the most exciting aspects of the movie is Nagano’s direct involvement: not only is the film adapted from their story, but Nagano is also writing the screenplay. Their personal supervision means the movie is likely to retain much of the original tone, character dynamics, and heart that made the arc so beloved. The film will be animated by CygamesPictures, a studio known for high production values. Directing the project is Kei Oikawa, who previously worked on Uma Musume - Pretty Derby.

Visuals & Teaser

The first teaser visual released for the film is atmospheric and poetic: Chiikawa, Hachiware, and Usagi are shown in a small boat, wearing flower crowns and grass skirts, under the glow of a full moon. This imagery underscores the dreamlike, tropical setting of the island and hints at both serenity and mystery. Nagano also shared a personal illustration alongside a message announcing the film, expressing their excitement that this “island story” is being brought to the big screen for the first time.

ちいかわ映画化決定しました！
２０２６年夏、公開予定ですhttps://t.co/WAW0fbBAAgpic.twitter.com/2afVnL6j5W

— ちいかわアニメ火金 (@ngnchiikawa)November 24, 2025

Nagano also shared a personal illustration alongside a message announcing the film, expressing their excitement that this “island story” is being brought to the big screen for the first time.

Image Credit: Nagano / 2026 "Chiikawa the Movie" Production Committee

Significance & Reception

This movie adaptation marks a significant moment for Chiikawa: despite the franchise's popularity, this is its first feature-length film. The choice to adapt the “Siren Arc” suggests confidence in the story’s depth and resonance, as this arc was particularly popular during its run. Nagano’s decision to write the screenplay themselves shows a commitment to preserving the story’s authenticity; many fans see this as a guarantee that the film will remain faithful to the original spirit.

For longtime Chiikawa fans, this film is a dream come true: a beloved story arc being realized in full animation, backed by the passion of its original creator. The “Siren Arc” is not just a cute side story — it's a more substantial, emotionally rich narrative, making it well-suited for the cinematic treatment.