Sonic X - North American Version

North American Version

Further information: 4Kids Entertainment#Editing and localization of anime

In 2003, 4Kids Entertainment licensed Sonic X for the United States, with the series being distributed on DVD by FUNimation, Alliance Films (Canada) and Warner Home Video (UK). The episodes were then localized for the intended demographic, including the complete replacement of the score, as well as removing suggestive content and changing the fate of several characters, as well as editing the story to be much lighter and younger in tone for US Release. Other continuity errors include mislabelling "Chaos Control" as Doctor Eggman's base. While both English and Japanese characters were digitally removed or replaced with incoherent symbols (This was done by TMS Entertainment themselves, rather than 4Kids.), Chinese characters were unedited in The Adventures of Knuckles and Hawk, in coherence with the episode's setting.

4Kids did not dub the Sonic games at the time and went with their in-house VAs. Mike Pollock, the current voice actor for Doctor Eggman, stated during an interview that he was provided samples of the game's voice overs as a reference. The original 4Kids cast included Jason Griffith (as Sonic and Shadow), Lisa Ortiz (as Amy), Amy Palant (as Tails), Dan Green (as Knuckles), Rebecca Handler (as Cream), and Mike Pollock (as Dr. Eggman).

As 4Kids owns the international distribution rights to Sonic X, the edited version of the show was then provided to most other countries around the world, including most of the countries of Latin America and Europe. The show was dubbed into the corresponding languages for each country, but the footage had the edits already made in the American version, along with the music changes. Furthermore, the scripts for the foreign dubs were based on the revised dub scripts of the American version rather than the original Japanese scripts, most likely as a way of maintaining consistency with the edited footage. The only other countries to receive their footage of Sonic X directly from Japan—without any of the edits made by 4Kids Entertainment—are France, China (including Taiwan and Hong Kong), South Korea, India, Sri Lanka, Vietnam, Thailand, Indonesia, Singapore, Malaysia and Philippines.

The cast of the 4Kids production eventually became the official cast for Sega's English localizations of the Sonic games from 2005 to 2010.

When a 4Kids producer for the series was asked about any prior experience with the Sonic franchise, he replied, "I've never played the game, seen the series or read the comics."

However, in July 2009, 4Kids uploaded a preview for a subtitled episode of the Japanese version of Sonic X. Season 1 of the Japanese version with English subtitles were uploaded to Hulu, along with the dubbed version of the complete series. More recently, the Japanese opening and closings were added to 4Kids' YouTube channel. On June 7, 2010, 4Kids had begun releasing Season 1 in Japanese on their YouTube channel. By June 11, 2010, the dubbed version of the complete series and the First Season in Japanese with English subtitles became available on 4Kids' YouTube channel. On August 13, 2012, all Sonic X episodes were removed from 4Kids' YouTube channel and Toonzai website.

As of 2012, Saban Brands (subsidiary of Saban Capital Group) owns the North American rights to Sonic X after acquiring it from 4Kids Entertainment and is now airing Sonic X on their Vortexx block. Currently it's the 4kids dub being aired, with no plans from Saban to produce a new English dub.