Radiant Emerald is the final track in Sonic R. It is unlocked by beating all tracks in first place. Eggman is unlocked here, by getting first place.
The area is sometimes thought to be inside the Master Emerald, due to its absence. It has been stated, though, that it is a magical rainbow that holds all the planets aligned. The track is considered the hardest in the game, mainly do to the flashing colours and various turns. It has a large Mobius Loop near the Beginning. It is the only track with a dead end if you were to take a wrong turn. As this track is the only course with no Tokens or Chaos Emeralds, the 2 50 Ring Doors act only as shortcuts in the race. One is at the beginning and has a Speed Booster. The Other is at the Middle and is just a quicker path. CPU's will usually activate the Ring Doors if they have enough rings to do so.
- This track has no weather and has a dead end, making it a unique track to the game.
- it is also the only track that has to be unlocked.