Chō Gekijōban Keroro Gunsō 2: Shinkai no Princess de Arimasu!

Keroro Gunso the Super Movie 2: The Deep Sea Princess is a 2007 Japanese animated comic science fiction film directed by Junichi Sato and Susumu Yamaguchi. It is the second film installment in the Sgt. Frog series created by Mine Yoshizaki and later adapted into Volume 20 of the manga in 2010. It premiered in Japan on 17 March, 2007 on a double feature with the computer animated prequel short film, Chibi Kero: Secret of The Kero Ball!? .

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.