Toy Kingdom is the fourth Zone in Sonic Advance 3, and is the only toy-themed level in the series to date, with different toys scattered throughout the level that are gimmicks or hazards; including jack-in-the-boxes that contain springs or spikes depending on the color of the diamond on the box, giant clackers, rockets to reach high places with and toy soldier enemies. There are also Carnival Night-esque balloons as well as elephant slides and cute panda Tea-cups for the player to ride, also suggesting it could be a theme park aimed at small children.
Like the other even-numbered zones, the third Act ends with a mini-boss fight with Gemerl, only this time the Gizoid has a new weapon: He'll fire missiles from his back that will home in on the lead player, but like previous encounters, he will go down after being hit four times (twice on Easy). If the player has Sonic in the lead and finishes Act 3, Amy Rose will be unlocked for use in the Main Game and Time Attack. Amy is listed as the last character in the intro and Character select screen, implying Cream would be unlocked here instead (with a zone-theme to match her personality), but instead, it is Amy.
- Bu-Bu - A robotic piggybank that moves back and forth. If the player loses their rings near one, it will suck them up.
- Gaogao - A wind-up lion robot that moves back and forth. It cannot be destroyed from the front due to its sturdy face.
- Guards - A trio of toy soldiers that march back and forth, shooting pellets from their trumpets.
- Juggling - A circus clown robot that patrols back and forth juggling pins (living up to its name).