• 
  Kumiko Asô

  Mother
• 
  Kôji Yakusho

  Grandfather
• 
  Gen Hoshino

  Father
• 
  Haru Kuroki

  Mirai-chan
• 
  Moka Kamishiraishi

  Kun-chan
• 
  Mitsuo Yoshihara

  Mysterious Man
• 
  Yoshiko Miyazaki

  Grandmother
• 
  Yoshiko Miyazaki

  Grandmother

• 
  John Cho

  Father (voice)
• 
  Daniel Dae Kim

  Grandfather (voice)
• 
  Masaharu Fukuyama

  Seinen (voice)
• 
  Rebecca Hall

  Mother (voice)
• 
  Matsunojo Kanda

  Robot of the Tokyo Station (voice)
• 
  Victoria Grace

  Mirai (voice)
• 
  Tasuku Hatanaka

  Male High School Student (voice)

• 
  Kaede Hondo

  Mirai-chan (baby) (voice)
• 
  Victor Brandt

  Grandfather (voice)
• 
  Erin Fitzgerald

  Additional Voices (voice)
• 
  Crispin Freeman

  Mysterious Man (voice)
• 
  Michael Sinterniklaas

  Additional Voices (voice)
• 
  Stephanie Sheh

  Great-Grandmother (voice)
• 
  Bella Hudson

  Additional Voices (voice)
• 
  Joe Thomas

  Station Agent (voice)
• 
  Jaden Waldman

  Kun
• 
  Evan Smith

  Kun (High Schooler)
• 
  Valerie Arem

  Grandma (Young) / Additional Voices (voice)
• 
  Cade Lappin

  Boy (voice)
• 
  Erick Abbate

  Boy