A Bonus Level is a level that is not actually part of a game put can be played once it has been unlocked.
- Finding all 12 secrets in the 4 normal levels of the Tomb Raider II Add-on The Golden Mask unlocks the secret level Nightmare in Vegas, which appears in the "New Game" menu. The secret level itself also features 3 secrets, though they serve no real purpose.
- Finding at least 59 secrets (it is possible to get 60) in Tomb Raider III unlocks the secret level All Hallows, which is played immediately after completing the Meteorite Cavern and watching the endgame credits.
- Completing All Hallows enables the player to start the game with all weapons and unlimited ammo, but it also triggers a severe bug, which forces the player to play only the India, Nevada, and Antarctica episodes of the game.
- Main article: Add-on
The Add-ons can also be considered bonus levels.