- Warrior - Default skin
- Warrior Dome - Unlock at Rank 4
- Warrior Ridged - Unlock at Rank 10
- Praetorian - Unlock at Rank 19
- Nethead - Unlock at Rank 34
- Specimen 6 - Pre-order only
There are noticeably fewer skins for the Aliens than the other two factions, with only 5 included in the game (plus an extra skin for those who pre-ordered). This is compared to 7 for each of the other factions (plus another pre-order bonus skin for each).
Several of the Xenomorph skins are based on designs from the movies — the standard Warrior is based on the original Warrior design in Aliens, the "Warrior Dome" variant is based on the creatures in Alien and Alien vs. Predator (which were actually Drones), the "Warrior Ridged" variant is based on the Warrior design in Aliens vs. Predator: Requiem and Nethead is based on Grid from Alien vs. Predator.
- Franco - Default skin
- Gibson - Unlock at Rank 2
- Van Zandt - Unlock at Rank 40
- Rookie - Unlock at Rank 28
- Johnson - Unlock at Rank 22
- Connor - Unlock at Rank 5
- Moss - Unlock at Rank 13
- Kaneko - Pre-order only
- Dark - Default skin
- Claw - Unlock at Rank 3
- Stalker - Unlock at Rank 7
- Spartan - Unlock at Rank 31
- Hunter- Unlock at Rank 16
- Wolf - Unlock at Rank 25
- Lord - Unlock at Rank 37
- Alien - Pre-order only
Several of the Predator skins are based on the Predators seen in the movies — Dark is based on the Jungle Hunter from Predator, Hunter is based on Celtic from Alien vs. Predator and Wolf is based on Wolf from Aliens vs. Predator: Requiem.
- There were rumors that the Abomination would be added as a DLC skin, although this ultimately proved not to be the case.
- Many have criticized the fact that there are no female marine skins (e.g. Corporal Tequila). Some have also criticized that there are no combat android skins for the Marines.
- The Claw skin is used in the game's single player campaigns for the members of the Young Blood Pack.
- Apparently the chosen skin can influence the player's voice/vocalizations. For example, a Praetorian skin has, reportedly, a "roaring" sound rather than the regular Xenomorph hissing.