The flashlight is a tool and weapon in Doom 3. Its default key is F (White for Xbox). Its main purpose is to light up dark corridors, although it can be used as a weapon at close range.
The flashlight does roughly twice as much damage as the player's fists. However, the range has reduced, and the attack rate is slower. On lower difficulties, the flashlight can be used to attack Zombies to conserve ammo (two hits will kill them), provided if the player can constantly back away before the enemy can land a hit. Attacking an enemy stronger than an Imp is not recommended. On higher difficulties, the flashlight should be used to light up dark corridors only, as the damage from even a Zombie increases drastically. The flashlight could also be used to shine light on any "sleeping" Zombies to awaken them, distinguishing them from dead corpses. In deathmatch, using the flashlight alerts other people to your whereabouts. The weapon is not included in the Xbox version's deathmatches.
- In multiplayer games, it is possible to toggle the flashlight on and off by pressing the reload key (R by default).
- There is a mod dubbed duct tape which provides an underbarrel flashlight for easier use in the darkness. This is a very commonly downloaded modification.
- The flashlight does not appear in the Xbox version of Doom 3 RoE. The flashlight, instead, is stuck to the pistol.
- In the BFG Edition, the flashlight has been replaced with a "mounted flashlight" on the Marine's armor. The new mounted flashlight only has a limited time period (roughly 30 seconds) to use before it has to recharge itself again. The world model for the red flashlight still exists, although the player can't take it.