Fumie Kashiyama as Marina (voice)

Mariko Miyagi as Fritz the Dolphin (voice)

Tarō Shigaki as Prince (voice)

Ichiro Nagai as Whistler (voice)

Kenichi Ogata as Oval Shark (voice)

Haruko Kitahama as Witch (voice)

Miyoko Asô as Mermaid Crone (voice)

Kazuko Sugiyama as Marina's Sister (voice)

Kazuko Sawada as Jemmy the Cat (voice)

Nana Yamaguchi as Prince's Mother (voice)

Rihoko Yoshida as Suomi Princess (voice)

Kaneta Kimotsuki as Crab / Conch (voice)

Kosei Tomita as Duke the Whale (voice)

Hidekatsu Shibata as Mermaid King (voice)