| United States|
| October 9, 2004 –
April 23, 2005|
Teenage Mutant Ninja Turtles' third season originally aired between October 9, 2004 and April 23, 2005, beginning with the "Space Invaders, Part 1" episode. The entire season of the television series was released on DVD in seven volumes from March 15, 2005 through May 16, 2006.
Teenage Mutant Ninja Turtles (2003 TV series) (season 3) Wikipedia
The Triceraton Republic launches a massive invasion of Earth, believing Professor Honeycutt to be hiding on the planet. After wreaking havoc on the planet, they are convinced to leave by Donatello, who reveals Honeycutt's departure, only for Honeycutt to return to Earth, intending to surrender himself to the Triceratons. The Turtles and Honeycutt are abducted by the Earth Protection Force, led by Agent Bishop, who has allied with the Federation. While Traximus deposes Zanramon, Honeycutt sacrifices himself to upload a computer virus to the Triceraton and Federation fleet. Traximus jails Zanramon and Blanque and declares a new era of peace, but the damage has been done to Earth. Having observed from the sidelines, Shredder uses his Oroku Saki persona to help in the reconstruction of New York, secretly salvaging Triceraton technology for an unknown purpose, while Bishop schemes to create an army of super-soldiers.
The Turtles and Splinter are visited by "Ultimate Drako", a fusion of Ve-Sama and Drako, who wield Lord Simultaneous' Time Scepter, and scatter the group across time and space. Michelangelo arrives in a world where the Turtles are superheroes fighting a villainous Splinter; Raphael enters the world of the Planet Racers franchise, Donatello suffers in an alternate timeline where the Shredder has conquered the Earth; and Leonardo arrives in Miyamoto Usagi's dimension. With help from Usagi, Leonardo travels to the Battle Nexus and is able to reunite his brothers and father, and defeat Ultimate Drako. Though the two are separated and Drako perishes, Ve-Sama is restored to a youthful form and reunited with his father.
After receiving a vision of the Shredder departing Earth to conquer the Utrom home world, Splinter rallies the Turtles, Casey, April, Leatherhead and Honeycutt (who were revealed to have survived their supposed deaths) to storm the Shredder's stronghold on the eve of his departure in a massive spacecraft. Bishop also enters the fray with Stockman on his side, but Shredder is able to lift off with Karai and Dr. Chaplin, with the Turtles and Splinter stowing away. As Bishop continues to assault the ship in space, the Shredder viciously wounds his foes, who decide to sacrifice their lives by detonating the ship's power core to kill the Shredder. Fortunately, the Utroms arrive just in time to save them all, and find Shredder guilty of numerous war crimes and atrocities, banishing him forever to a desolate ice asteroid.Michael Sinterniklaas as Leonardo, the leader of the Turtles. (26 episodes)
Wayne Grayson as Michelangelo, the Turtles' youngest member and a source of comic relief. (26 episodes)
Sam Riegel as Donatello, the Turtles' genius engineer who is identified as the member who holds the team together. (26 episodes)
Frank Frankson as Raphael, Leonardo's second-in-command who often argues with him. (26 episodes)
Darren Dunstan as Splinter, the Turtles' sensei and adopted father, who comes to realize his destiny as a guardian of the Utroms. (21 episodes (has no lines in episode 2))
Scottie Ray as Ch'rell/Oroku Saki/The Shredder, the main antagonist of the series and the leader of the Foot Clan, who uses his wealth to help repair New York for an ulterior motive. (9 episodes)
Veronica Taylor as April O'Neil, an ally of the Turtles who enters a relationship with Casey Jones. (14 episodes (has no lines in episodes 4 and 26))
Marc Thompson as Casey Jones, an ally of the Turtles who enters a relationship with April O'Neil. (15 episodes (has no lines in episode 4))
Scott Williams as Baxter Stockman, a brilliant scientist who often attempts to sabotage the Shredder for his own personal gain. (8 episodes)
Karen Neill as Karai, the Shredder's adopted daughter and second-in-command, whose allegiance and devoted service come into question, as Leonardo tries to convince her to change sides; probably because of his romantic affections toward her.
Greg Carey as Hun, a hulking gangster who struggles to stay in the Shredder's favor after several failures.
David Zen Mansley as Agent John Bishop, a black ops agent in charge of the Earth Protection Force, an organization devoted to defending Earth from alien invasion.
Sam Riegel as Dr. Chaplin, a young scientist who threatens not only Stockman's place in the Foot hierarchy, but his life as well.
Michael Alston Bailey as Zanramon, the despotic Prime Leader of the Triceraton Republic who invades Earth to find Professor Honeycutt.
Dan Green as Commander Mozar, a seasoned veteran who serves as Zanramon's second-in-command.
Jason Griffith as Miyamoto Usagi, an ally of the Turtles who Leonardo encounters during an impromptu visit to his dimension.
F.B. Owens as Traximus, an honorable Triceraton gladiator the Turtles befriended in the previous season, now a leader of a rebel cell who seek to dethrone Zanramon; Leatherhead, a mutant alligator who is a loyal ally of the Turtles.
Ted Lewis as Ve-Sama, a warrior prince who goes by the title "Ultimate Ninja", who merges with Drako and seeks vengeance on the Turtles.
Marc Thompson as Drako, an enemy of Splinter who is merged with Ve-Sama and seeks revenge on him.
Mike Pollock as General Blanque, the leader of the Federation.
Oliver Wyman as Fugitoid/Professor Honeycutt, a Federation scientist whose mind was accidentally uploaded into an android's body, who possesses the plans for a teleportation device warred over by the Triceratons and Federation.
Teenage Mutant Ninja Turtles was produced by Mirage Studios, 4 Kids Entertainment, 4Kids Productions, and Dong Woo Animation and distributed by 4 Kids Entertainment and was aired on Fox's Saturday morning kids' block in the US. The producers were Gary Richardson, Frederick U. Fierst, and Joellyn Marlow for the American team; Tae Ho Han was the producer for the Korean team.