One of the most exciting aspects of Injustice is the ability to customize your favorite characters with various skins and alternate costumes. These range from classic comic book appearances to entirely new designs. Many are unlocked by completing S.T.A.R. Labs missions, specific Battle Mode ladders, or by purchasing DLC packs. Collecting them all adds significant replay value.

- Story Mode Unlocks: Some skins are earned by completing the main story.
- S.T.A.R. Labs Rewards: Specific missions grant character-themed costumes.
- Battle Mode Endings: Completing certain ladders can unlock unique skins.
- DLC Packs: Additional costumes are available for purchase.
- Season Pass: Often includes exclusive character skins.