Bo Jakobsen
— Benny (voice)
Jesper Klein
— Tadpole (voice)
Peter Belli
— Octopus (voice)
Jytte Abildstrøm
— Dagny (voice)
Otto Brandenburg
— Lobster Boy (voice)
Jytte Hauch-Fausbøll
— Benny's Mother (voice)
Rolf Krogh
— Ornithologist (voice)
Povl Dissing
— First Pirate (voice)
Per Goldschmidt
— Second Pirate (voice)
Per Tønnes Nielsen
— Cowboy (voice)
Aya
— Mermaid (voice)
Maia Årskov
— Mermaid (voice)
Trille
— Mermaid (voice)
Christian Sievert
— Crab (voice)
Allan Botschinsky
— Seahorse (voice)