The Last Arbender:
Aang: Asa Butterfield (Hugo Cabret)
Katara: Hailee Steinfeld (True Grit)
Sokka: Suraj Sharma (Life of Pi)
Toph: Isabelle Fuhrman (Orphan)
Ozai: Ken Watanabe (Inception)
Ursa, mother of Zuko and Azula: Raiko Bowman (The Hunger Games)
Zuko: Ezra Miller (We Need to Talk About Kevin)
Azula: Ellen Page (Juno)
Iroh: Min-sik Choi (Oldboy)
Mai: Crystal Liu Yifei (The Forbidden Kingdom)
Ty Lee: Emily Marie Palmer (Crisis of Faith)
Jet: Avan Jogia (Triple Dog)
Suki: Shailene Woodley (The Descendants)
Yue: Vanessa Hudgens (Sucker Punch)
Haru: Booboo Stewart (The Twilight Saga)
Teo: Aramis Knight (The Dark Knight Rises)
Mechanist, dad of Teo: And Serkis (The Hobbit)
King Kuei: James Kyson Lee (Hawaii Five-0)
Long Feng: Hiroyuki Sanada (Speed Racer)
Zhao: Donnie Yen (Yip Man)
Hama: Lorna Raver (Drag to Me Hell)
June: Maggie Q (Priest)
Combustion Man: Randy Couture (The Expendables)
Avatar Kyoshi: Lucy Liu (Kill Bill)
Avatar Roku: Chow Yun-Fat (Pirates of the Caribbean: At World's End)
Pakku: Bill Nighy (Total Recall)
Master Piandao: Jackie Chan (Rush Hour)
Jeong Jeong: Jet Lee (The Expendables)
Bumi: Chistopher Lloyd (Fringe)
Hue: Kevin McNally (Pirates of The Caribbean)
Due: Mackenzie Crook (Pirates of The Caribbean)
Tho: Lee Arenberg
Hakoda: Rodirgo Santoro (300)
Kya: Ildi Silva (Gabriela)
The Legend of Korra:
Korra: Naomi Scott (Terra Nova)
Mako: Aaron Johnson (Kick-Ass)
Bolin: Josh Peck (Red Dawn)
Asami: Jamie Chung (Sucker Punch)
Tenzin: Jeff Bridges (Iron Man)
Lin Beifong: Carla Gugino (Sucker Punch)
Amon: Javier Bardem (007 Skyfall)
Tarrlok: Jeffrey Dean Morgan (Watchmen)
Yakone: Kevin Spacey (Horrible Bosses)
General Iroh: Harry Shum Jr. (Glee)
Sato: Sammo Hung Kam-Bo (Yip Man 2)