A new 90-second trailer for Chiikawa the Movie: The Secret of Mermaid Island reveals two new cast members and the opening theme ahead of the July 24 Japanese theatrical release.
Chiikawa the Movie: The Secret of Mermaid Island has dropped a new 90-second trailer that reveals two fresh cast additions and the film's opening theme song. The anime feature is set to premiere in Japanese theaters on July 24, 2026.
Veteran voice actor Tsuguo Mogami joins the cast as Shimajiro, a shopkeeper the main characters encounter on their island adventure. Singer and voice actress Minori Suzuki takes on the role of Siren, a massive mer-creature whose mysterious song draws the protagonists deeper into the island's secrets.
The returning cast remains intact from the television anime series. Haruka Aoki reprises the title role of Chiikawa, Makoto Tanaka returns as the ever-loyal Hachiware, and Ari Ozawa once again voices the chaotic Usagi. Together, the trio sets off on a journey to an island that promises generous rewards in exchange for completing tasks a premise fans of the manga's "Siren Arc" will recognize immediately.
The trailer prominently features the film's opening theme, "Kutsuzure," performed by Makoto Tanaka in character as Hachiware. Series creator Nagano wrote the lyrics for the track, maintaining the deeply personal creative throughline that has defined the Chiikawa franchise from its earliest web-manga days. The choice to have Hachiware arguably the most expressive and musical of the main trio perform the opening feels like a natural fit for a story centered on a siren's song.
Kei Oikawa directs the film at studio CygamesPictures, with Nagano credited for both the original story and the screenplay. The movie adapts the manga's Island Arc, sometimes referred to as the Siren Arc, one of the longer and more narratively ambitious storylines in the source material. The arc follows Chiikawa, Hachiware, and Usagi as they travel to a remote island lured by the promise of "basically free" food and hidden rewards, only to discover the island holds far more dangerous secrets than anticipated.
The Chiikawa franchise has grown enormously since Nagano first began posting one-panel comics on social media in 2020. The TV anime adaptation, which began airing in 2022, helped push the series into the mainstream, and the brand's merchandise line has become one of the top-selling character goods franchises in Japan. A theatrical film represents a significant step up in scale for the property.
With the July 24 premiere now less than two months away, additional promotional material including a full-length trailer and details on advance ticket sales is likely on the horizon. No international distribution plans have been confirmed at this stage, though the franchise's growing global fanbase and existing streaming presence suggest an announcement may follow closer to the Japanese opening.
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