- Anthony Anderson
- Ray
- Ed Begley Jr.
- GreenPeace Worker
- Pat Carroll
- Old Female Turtle
- Tim Curry
- Fluffy
- Stacy Keach
- Grandpa Sammy
- Yuri Lowenthal
- Young Sammy / Ollie (voice)
- Kathy Griffin
- Vera
- Melanie Griffith
- Snow
- Jenny McCarthy-Wahlberg
- Shelly
- Charlie Adler
- Slim
- Gigi Perreau
- Whale
- Roxanne Reese
- Rita
- Cam Clarke
- Seagull / Additional Voices (voice)
- Darren Capozzi
- Robbie
- Alan Shearman
- Old Turtle
- James Fredrick
- Fisherman #1
- Scott Menville
- Jacko / Additional Voices (voice)
- W.K. Stratton
- Fisherman #2
- Wolfgang Wesley Hutton
- Baby Buddha
- David Jolliffe
- Lab Worker
- Richard Jannone
- Policeman
- Kierstin Koppel
- Female Turtle #2
- Al Rodrigo
- Ben, VW Driver
- S. Scott Bullock
- Large Seal
- Donald Fullilove
- Green Turtle / Additional Voices (voice)
- Joey Naber
- GreenPeace Worker
- Olivier Paris
- Loggerhead
- Leo Howard
- Hatchling
- Carlos McCullers II
- Hatchling Ray
- Isabelle Fuhrman
- Hatchling Shelly
- Sam Riebs
- Hatchling
- Eric Unger
- Hatchling #1
- Krista Williams
- Hatchling
- Grant Klemann
- Hatchling #2
- Keegan Michael Thomas
- Baby Hatchling
- Steve Kramer
- Additional Voices
- Heather Trzyna
- Hatchling / Young Loggerhead Sally (voice)
- Keith Anthony
- Additional Voices
- Steve Staley
- Additional Voices
- Archie Hahn
- Additional Voices
- Charlie Schlatter
- Additional Voices
- Pamela Adlon
- Female Turtle #1 / Additional Voices (voice) (as Pam Adlon)
- Gemma Arterton
- Shelly
- Sydney Hope Banner
- Loggerhead Turtle
- Ben Bishop
- VW Driver / Male Hatchling #1 / Male Hatchling #2 / Ollie / Loggerhead Turtle 1 / Loggerhead Turtle 5 / Loggerhead Turtle 7 / Crowd / Fisherman #1 / Police #1 / Large Seal / Green Turtle / Old Male Turtle / Ben (voice)
- Julia Boecker
- Baby Buddha
- William Brent
- Hatchling Sammy
- Chris Andrew Ciulla
- Snow Crab
- Dominic Cooper
- Sammy
- Melanie Cooper
- Snow
- Dennis Cruzado
- Shark
- Tim Dadabo
- Policeman
- Ray Gillon
- Male Hatchling #3 / Crowd / Fisherman #2 / Hippie #2 / Police #2 / Greenpeace Worker #2 / Greenpeace Worker #3 / Lab Worker (voice)
- Bridget Hoffman
- Additional Voices
- John Hurt
- Grandpa Sammy
- Sohm Kapila
- Rita
- Christine Lampard
- Sandra
- Anjella Mackintosh
- Female Hatchling / Loggerhead Turtle 2 / Vera / Old Female Turtle (voice)
- Kayvan Novak
- Fluffy / Slim / Seagull / Robbie (voice)
- Stephanie Powter
- Female Turtle #2 / Young Female Turtle (voice)
- Geoff Searle
- Jacko / Loggerhead Turtle 3 / Loggerhead Turtle 4 / Loggerhead Turtle 6 / Loggerhead Turtle 8 / Crowd / Hippie / Whale / Greenpeace Worker #1 / Hatchling Turtle (voice)
- Robert Sheehan
- Ray
- Georgia Sweeney
- Female Turtle #1 / Female Turtle (voice)
- Adam Wylie
- Additional Voices
- Dany Boon
- Samy adulte
- Patty Brard
- Vera
- Charlotte ten Brink
- Shelly
- Valentin Cherbuy
- Samy Jr.
- Clara Cleymans
- Snow
- Sven De Ridder
- Fluffy
- Griet Dobbelaere
- Shelly
- Guillaume Gallienne
- Alphonse
- Carry Goossens
- Slim
- Wouter Hendrickx
- Opa Sammy
- Kevin Janssens
- Sammy
- Nurlaila Karim
- Rita
- Frits Lambrechts
- Slim
- Annie Milon
- Rita
- Sofie Palmers
- Vera / Rita (voice) (uncredited)
- Olivia Ruiz
- Shelly adulte
- Mathijs Scheepers
- Ray
- Elie Semoun
- Ray adulte
- Serge-Henri Valcke
- Pluisje
- Hanna Verboom
- Sneeuw
