Zombies serve as an active hazard to players in Unturned (version 3). They are hostile entities that can be found throughout the playable maps. Zombies are drawn to motion and sound, such as players within their cone of vision, running vehicles, gunshots, nearby melee attacks, and thrown objects that land near them. They can also be attracted by specific kinds of player-activated light sources, such as from a Flashlight, Headlamp, or Tactical Light. Zombies will attack vehicles, barricades, and player-built structures if they cannot find a way around them. They make passive sounds periodically when idle, and growl when alerted.
If a player does a certain amount of damage to a zombie with a single hit, the zombie will be stunned. For most zombie variants, this threshold is 20 damage in a single hit. For mega zombies and zombie bosses, this threshold is 150 damage in a single hit.
Zombies can appear in many different variants. These variants are sometimes referred to as "specialties".
- Zombie, also known as the "normal zombie", targeting the player's body.
- "Crawler", which slowly crawls on the ground. Deals 2x damage, targeting the player's legs, and has 1.5x health.
- "Sprinter", which quickly runs on all fours. Deals 0.75x damage, and has 0.5x health. Has a slightly increased detection radius.
- "Burner", which explodes in a burst of flames that deals additional close-range damage and can spread to other zombies. This burst of flames can be negated if the player is wearing a Firefighter Top and Firefighter Bottom. Can be easily identified due to being continuously engulfed in flames.
- "Flanker", which can turn partially invisible and attempts to stealthily attack players from the sides or behind. They are visually indistinguishable from normal zombies until alerted, and are coloured a faint purple hue while invisible.
- Acid Zombie, also known as the "Acid Spitter". Has a long-ranged acid spit attack that leaves behind a large damaging area of effect. Can be identified by glowing blue acid gushing out of its mouth.
- Spirit Zombie, which takes significantly reduced damage from ranged weapons. Gun damage is reduced to 10%. Can be identified as mostly transparent with a gray hue, and by their higher pitched noises.
- Mega Zombies, which attack the player's head and can throw boulders. Only one mega zombie can exist in an individual navmesh at a time, and only two mega zombies can be present on a map at any given moment. After having been defeated, or otherwise despawned, another mega zombie cannot appear in the same navmesh until ten minutes have passed. Mega zombies can be easily identified by their massive size and their deeper noises.
- Hyper Zombies, which are zombies affected by an ongoing full moon. Hyper zombies are more dangerous than their normal counterparts in multiple ways, including increased damage and detection radius. Their eyes glow red to indicate these changes. When the full moon ends, hyper zombies are once again reverted to regular zombies.
- Radioactive Zombies, which are zombies found in deadzones. Radioactive zombies explode in a burst of glowing green, bio-hazardous material when killed, dealing both health damage and immunity damage to the player if they are too close. Can be identified by a glowing green aura.
As a part of the promotional crossover event with Dying Light, volatiles used to be able to spawn during the night. When daytime came, they would immediately burst into flames and die.
- Blue Volatile
Like mega zombies, zombie bosses are larger and stronger than normal zombies.
- Groundpounder Zombie Boss, also known as the "Wind Boss". Has 6,000 health. Periodically jumps and slams into the ground with great force, dealing damage in a radius around itself.
- Stomper Zombie Boss. Has 4,600 health. Gun damage is reduced to 10%.
- Lightningstrike Zombie Boss, also known as the "Electric Boss". Has 6,000 health. Periodically attacks the player at range with a blue lightning bolt, which can be stopped by cover. Can be easily identified due to being surrounded by glowing blue particles of energy.
- Flamethrower Zombie Boss, also known as the "Fire Boss". Has 6,000 health. Periodically uses a ranged fire-breathing attack which rapidly deals damage, and bursts into flames upon death; both of which can be negated by wearing firefighter clothing. Can be easily identified as it is always on fire.
- Nuclear Spitter Zombie Boss, also known as the "Nuclear Boss" or "Radioactive Boss". Has 6,000 health.
- Spirit Zombie Boss. Has 6,000 health. Gun damage is reduced to 10%. Similar to a typical spirit zombie in appearance, but larger.
- Magma Zombie Boss. Has 12,000 health. Characteristics resemble that of the Flamethrower Zombie Boss, but it is covered in magma.
- "Cursed Pirate Zombie Boss" and "Kaiser Zombie Boss". Has 12,000 health.
- Evil Eye Zombie Boss, also known as the "Kuwait Boss". Periodically throws boulders, or summons an Evil Eye that can cause a flashbang effect. Has 60,000 health.