Route 99 is the first zone in Sonic Advance 3. It breaks from the usual routine of the tropical island theme being the first level of the game, as it is a big city with yet-uncommon obstacles. It is the starting point of Sonic and Tails' adventure after being separated from their friends by Eggman's world-shattering experiments with Chaos Control.
This mess of highway features a lot of straightaways to allow you to become accustomed to the game's high speeds, as well as some simple platforming, switch puzzles and rails to get you used to the Tag Action-based gameplay. Gimmicks include moving boxes, Star Light Zone-style see-saws, poles which launch you upwards, corkscrew bridges, and wheels that, when performing a Spin Dash on, open up optional platforming segments. Dangers include badniks, spike pits, death by crushing, and a brief bottomless pit near the end of Act 1.
The music for this zone incorporates elements of the theme for Tails' Lab from Sonic Battle. Its music was later remixed for Sonic Generations, Mario & Sonic at the Sochi 2014 Olympic Winter Games and Mario & Sonic at the Rio 2016 Olympic Games.
- Akatento - A mechanical ladybug similar to a Moto Bug. Red ones patrol back and forth, blue ones fly up in the air when approached.
- Condor - This falcon badnik flies in the air and attacks by dropping bombs or by charging at the player.
- Spina - The familiar bat-like badnik that hovers in place, spinning its blades.