- All-Star Cast:
- As with all Ghibli films since 1997, quite a few famous Japanese actors and comedians provide several roles in the film, such as Tomoko Yamaguchi, George Tokoro, Kazushige Nagashima, Yuki Amami, Tomoko Naraoka, and Kazuko Yoshiyuki. Rumi Hiiragi, who voiced Chihiro in Spirited Away, voices the young mother.
- While Disney has always been able to find a few famous actors to do the English dubs of Ghibli films and Kingdom Hearts, this movie seriously takes the cake. With a cast including Matt Damon, Tina Fey, Cate Blanchett, Liam Neeson, Betty White, Lily Tomlin, and Cloris Leachman.
- Approval of God: Hayao Miyazaki was impressed by the film's English dub.
- Children Voicing Children: Ponyo and Sosuke are voiced by actual young children.
- No Export for You: The film was released on VHS (being the last film to get a wide VHS release) but this version only came out in Japan.
- Production Posse: Executive producer Kathleen Kennedy and writer Melissa Mathison worked together on E.T. the Extra-Terrestrial.
- Promoted Fanboy: Fujimoto's English VA Liam Neeson was familiar with Miyazaki's works before he was cast.
- Reality Subtext: Miyazaki made Ponyo as a means of trying to reconcile with his estranged son (the one who directed Tales from Earthsea). Throughout the film, Sosuke and his father are separated.
- Real-Life Relative: Joe Hisaishi's daughter Mai sings vocals on several cues of the film's score. Mai even sang the image song "Rondo of the House of Sunflowers".
- She Also Did: The English dub's screenwriter, Melissa Mathison, previously worked on E.T. the Extra-Terrestrial.
- The English dub's executive producer, Kathleen Kennedy, is the current leader of Lucasfilm (which also produced the English dub through Skywalker Sound) and the producer of the newer Star Wars films and shows.
- So My Kids Can Watch: For the English dub, Megan Marshall, the daughter of the English version's executive producers Frank Marshall and Kathleen Kennedy, suggested that Frankie Jonas and Noah Cyrus should play Sosuke and Ponyo, respectively.
- Studio Hop: Ponyo is the first Studio Ghibli film to have its English dub recorded at Skywalker Sound instead of Buena Vista Sound Services, which was re-branded as Disney Digital Studio Services Sound Department in 2009.
- Written for My Kids: A sad variant; as noted in Reality Subtext above, Miyazaki wrote the film with his own estranged son in mind.
- What Could Have Been: Miyazaki wanted to do a sequel to the film, however Ghibli producer Toshio Suzuki didn't want a sequel and suggested he do a film based off of famed plane engineer and designer Jiro Horikoshi instead, which he wasn't initially keen on at first, but eventually got behind it. While this did lead to the critically acclaimed The Wind Rises, one can't help but wonder what a Ponyo sequel could have looked like.
- Believe it or not, according to Miyazaki, Ponyo was originally a tin wind-up toy frog. Because of the strange concept, he changed her to a fish who shifts into an amphibian creature at times.
- This film was the very last film to get a wide retail VHS release, being released on VHS in Japan only in 2009.
Trivia / Ponyo on the Cliff by the Sea