Teleporter

Teleporters allow for instantaneous transport over short distances to another teleporter or teleporter exit point. Although they act similarly to Halo's teleportation grid, they are unable to transport over long distances. In Multiplayer, these are seen on levels such as Blood Gulch and Beaver Creek. In multiplayer maps, however, teleporters can be found on Earth. It is unknown about the canonicity of teleporters on certain maps.

In Halo 3, teleporters were not present in any multiplayer map because Bungie thought it was too easy to "camp" near them and get easy kills. Despite this, teleporters were reintroduced in the recently released map Avalanche, as well as appearing on Cold Storage. Teleporters are available, however, in Forge for every Halo 3 map. In Halo 3, when a person enters a teleporter and is going at a higher speed (most likely caused by a jump from above), they keep their momentum and come out at the same speed, but in the direction it is aiming.

List of Maps with Teleporters
Halo: CE:
 * Battle Creek
 * Blood Gulch
 * Boarding Action
 * Chill Out
 * Chiron TL-34
 * Damnation
 * Danger Canyon
 * Death Island
 * Derelict
 * Gephyrophobia
 * Ice Fields
 * Infinity
 * Rat Race
 * Sidewinder
 * Wizard

Halo 2:
 * Ascension
 * Beaver Creek
 * Coagulation
 * Containment
 * Gemini
 * Headlong
 * Relic
 * Warlock
 * Waterworks

Halo 3: ''Note: Every map in Halo 3 can have teleporters placed in Forge. The maps listed are ones that have teleporters by default.''
 * Avalanche
 * Cold Storage

Trivia

 * In Halo 2, if the exit end of a teleporter is obstructed by a player, and another tries to get through the entry end, the obsturcting player will die after a few seconds.
 * The canon nature of teleporters are debatable, as they are never mentioned in any canon material. Bungie has stated, however, that multiplayer maps themselves are canon.
 * In Halo 3, except for the couple of maps with teleporters listed above, the teleporters on other maps only appear in Forge. Bungie, however, provided the gamers with the Man Cannon, a different way of quickly going through the map.
 * A clever, though usually considered cheap, strategy involving teleporters is to go through one, then immediately move backwards. If the space behind it goes back far enough, then you can camp behind the teleporter. This only works with two-way teleporters.
 * On Cold Storage and Gemini, the teleporters are blue instead of the normal green.
 * You cannot throw a grenade nor shoot through a teleporter, so there's no hope to teleport projectiles and get lucky, cheap kills.