Chiikawa the Movie: The Secret of Mermaid Island (Eiga Chiikawa: Ningyo no Shima no Himitsu) continues its staggering theatrical run, having grossed an impressive 15.84 billion yen (approximately US$100.5 million) domestically in Japan according to updates from the official X account.
With this milestone, the mascot franchise's cinematic debut has overtaken Detective Conan: The Million-dollar Pentagram to secure the 16th position on Japan's all-time highest-grossing film list, standing comfortably as the top-performing release of 2026 so far. International markets are also embracing the feature, with screenings rolling out across Southeast Asia and global box office estimates reaching roughly US$159 million.
Production and Franchise Origins
Originating in 2020 as a deceptively simple X (formerly Twitter) webcomic by creator Nagano, the adaptation brings the beloved Siren Arc to the big screen. The film is directed by Kei Oikawa, known for his work on Umamusume: Pretty Derby Seasons 1 and 2, with animation production handled by CyPic. Nagano contributed directly to the screenplay, while Tomoko Tsuji returned as character designer.
Hachiware and his friends find a brochure promising rewards and free food on a “special island”. Lured by the offers, they board with skeptical sea otters and arrive at the mysterious island.
GSC Synopsis
The broader multimedia phenomenon includes a massive Doga Kobo-produced television short series spanning over 370 episodes, alongside physical tankobon releases and physical attractions like the 2025 Chiikawa Park in Ikebukuro. Having claimed the prestigious Japanese Character Award Grand Prix in 2022, 2024, and 2025, the property solidifies its cultural permanence with this historic box office victory.
