Modern Warfare 3 Operators are unlocked by completing challenges, finishing campiagn missions, or by purchasing Battle Passes and store bundles.

The Lachmann Sub in Warzone and Modern Warfare 3 is an SMG returning from the previous game and one commonly known by players as the MP5. The Lachmann Sub - or MP5 - is available to acquire, use, and customise in Modern Warfare 3 as part of the new Carry Forward system introduced with the release of the game.