Instructions
Search the Serebii Event Database or view the official Pokemon website's "News and Events" page to learn about upcoming Nintendo events. Nintendo gives players several different Pokemon, including Celebi, during these events. Bring your Game Boy Advance and your copy of "FireRed" to any event.
Acquire the Japanese "Pokemon Colosseum" Bonus Disc, sold new and used by retailers and second-hand merchants. This method will only work if you possess a Japanese version of "FireRed" or another "Pokemon" Game Boy Advance game, an English version of "FireRed" and a Japanese GameCube. Insert the disc into the GameCube.
Capture and purify all 48 Pokemon, according to the "Pokemon Colosseum" storyline. Defeat the Elite Four and save your game. Leave one space open in your Pokemon party and save your game. Place the bonus disc into your GameCube to receive Celebi into your party.
Insert a Japanese "Pokemon" game into the Game Boy Advance. Connect your GameCube and Game Boy Advance systems using a GameCube and Game Boy Advance link cable to download Celebi to your Game Boy Advance game.
Enlist a friend's assistance. Insert your English version of "FireRed" into a second Game Boy Advance system. Your friend will play the Japanese "Pokemon" game. Connect both systems using a Game Boy Advance link cable and turn on the systems.
Travel to a Pokemon Center and speak to the Cable Club representative to initiate trade with your friend. Your friend will trade Celebi to the English version of "FireRed." Accept the trade and save your game.