- Cast the Runner-Up:
- Moka Kamishiraishi (18 years old at the time of release) originally auditioned to be the voice of Mirai. At the audition, Hosoda asked her to try out for the role of Kun (despite expecting to cast either a child actor or a veteran adult voice actress), and she ended up with the role of Kun.
- Coincidentally Mirais eventual voice actress Haru Kuroki originally auditioned to voice Kun.
- Celebrity Voice Actor:
- As with all of Mamoru Hosoda's films since 2006, Mirai features celebrities voicing the main characters. In the original Japanese version, Kun is played by actress Moka Kamishiraishi, the titular character is voiced by film and drama actress Haru Kuroki, Kun's parents are voiced by singer-songwriter/actor Gen Hoshino and actress/model Kumiko Asō, and Kun's great-grandfather is voiced by jidaigeki and film actor Kōji Yakusho.
- Ditto with the English dub, which features Jaden Waldman as Kun, Victoria Grace as Mirai, John Cho as Kun's father, Rebecca Hall as Kun's mother, Victor Brandt as Kun's grandfather, and Daniel Dae Kim as Kun's great-grandfather.
- Children Voicing Children: Kun's English VA, Jaden Waldman, was 7 years old when the dub was recorded.
- Relationship Voice Actor: The Latin American Spanish dub is basically a reunion of many alumni from the dub of the Dragon Ball franchise:
- Laura Torres (Kun) is young Goku, Gohan and Goten.
- Susana Moreno (Mirai) is young Mai in Dragon Ball Super.
- Eduardo Garza (Kun's father) is adult Krillin.
- Cristina Hernández (Kun's mother) is Marron, which is Krillin's daughter, hilariously enough.
- José Gilberto Vilchis (Great-grandfather) is Zamazu.
- Studio Hop: Whereas the previous Mamoru Hosoda's films were distributed by Funimation in North America, Mirai is the first film to be released by GKIDS.
- Write Who You Know: Mamoru Hosoda based several elements of the film off his own family experiences. Kuns jealousy of Mirai mirrors his elder childs jealousy toward his younger sister, and Kun seeing middle school-age Mirai is taken from a dream in which his older child saw his sister at that age. He also based Kuns great grandfather off his wifes grandfather.
Trivia / Mirai of the Future