A Service Tag is a tag meant to identify players quickly during a match. They consist of one letter and two numbers in Halo 3 and an arbitrary combination of 4 letters or numbers in Halo 3: ODST, Halo: Reach, and Halo 4. In team games, they appear above a player's head with a marker indicating their position, even through walls. When the player's reticle is pointed directly at the player, the full Gamertag is displayed instead.
It is beneficial for a player to set his service tag to be identical to his Gamertag so his teammates can more easily identify him.
List of Prohibited Service Tags
Some service tags are not allowed because they are vulgar, offensive, reserved, or copyrighted. These are not complete lists and are added to over time.
Halo 3
- Every service tag ending in 00
- A01 - Resembles AOL
- A20
- A23 - Reserved by UNSC
- A55
- C17
- E51
- E74 - Resembles the Red Ring error code E-74
- E43 - Resembles 343 in 343 Guilty Spark
- F03 - Resembles Fallout 3
- F43
- F46
- F48
- F49
- I17
- L17 - Reserved by UNSC
- N34
- N64 - Represents Nintendo 64
- N84
- P51 - Resembles "PS1"
- P52 - Resembles "PS2"
- P53 - Resembles "PS3"
- T17
- U50
- V50
- Z17
- 117 - Reserved by UNSC
Halo 3: ODST
- C0DY
- B4K4
- C0CK
Halo: Reach
- S117 - John-117's service number
- UNSC
- Sll - Resembles Spartan II
- 7 - Bungie's favorite number
- 0000
- Slll - Resembles Spartan III
- WIKI - Used by Halo Nation members
- RVB - Stands for Red vs Blue, a machinima series by Rooster Teeth
- 343I - Stands for 343 Industries
- AN - Stands for Allied Nations
- NOOB
- HALO
- JOHN
Halo 4
- 343I - Stands for 343 Industries
Trivia
- In Halo 3, when I17 is entered as a service tag, a message displays that says, "this service tag is currently reserved by the UNSC."
- A prohibited service tag can be used if it was randomly assigned to the player upon profile creation.