In the Bonus level, the playable character flies through an empty space where the goal is to collect as many Rings as possible before the level ends.
The Bonus level is a purplish black-blue space dotted with numerous stars in different colors. The upper and lower edge of the level is covered in purple and bluish gas clouds.
After passing a Goal Plate with a Bonus item, the player is automatically sent into the Bonus level. Within the Bonus level, the playable character is surrounded in a multicolored area and flies forward nonstop. The entire level is free of obstacles and enemies, meaning the player can move around to their heart's content. To move up in here, the player has to tap and hold the screen. To go down, they have to release the screen.
Along the way, the player will come across various clusters of Rings and Super Rings in certain formations, which the player can pick up to rank up their score or unlock contents in Sonic Runners Adventure. A Bonus level lasts for about 15–25 seconds before ending automatically and returning the player to the Result screen.
- Many of the Ring clusters in the Bonus level are shaped like certain objects, such as arrows, and some even spell out words like "NICE" and "RINGS". In fact, the end of a Bonus level is normally marked with a Ring cluster spelling out a word.
- The Bonus level is very similar to the "Fever Mode" of Sonic Jump Fever.
- The music for the Bonus level is a remix of the music for the Indigo Asteroid.