- Longshore Skull
Halo 3: Find the hidden Skull on the Longshore multilayer map.
- Heretic Skull
Halo 3: Find the hidden Skull on the Heretic multiplayer map.
- Sandbox Skull
Halo 3: Find the hidden Skull on the Sandbox multiplayer map.
- Orbital Skull
Halo 3: Find the hidden Skull on the Orbital multiplayer map.
- Assembly Skull
Halo 3: Find the hidden Skull on the Assembly multiplayer map.
- Witch Doctor
Halo 3: Find and claim all Skulls in Halo 3.
- Skulltaker Halo 3: Mythic
Halo 3: Find and claim the Mythic Skull on Normal or harder.
- Skulltaker Halo 3: Tilt
Halo 3: Find and claim the Tilt Skull on Normal or harder.
- Skulltaker Halo 3: IWHBYD
Halo 3: Find and claim the IWHBYD Skull on Normal or harder.
- Go, Chief! Gun It!
Halo 3: Beat the par time on Halo.
- Speed Demon
Halo 3: Beat the par time on all Halo 3 levels.
- Training Wheels
Halo 3: Complete every level of the game on Easy difficulty.
- Return
Halo 3: Complete Halo.
- The Key
Halo 3: Complete Cortana.
- Making History
Halo 3: Beat the par time on Cortana.
- Skulltaker Halo 3: Thunderstorm
Halo 3: Find and claim the Thunderstorm Skull on Normal or harder.
- Flipyap
Halo 3: Listen to the tale of a young Grunt named Flipyap.
- Last Stand
Halo 3: Complete The Covenant.
- Scarab Slide
Halo 3: Beat the par time on The Covenant.
- Skulltaker Halo 3: Cowbell
Halo 3: Find and claim the Cowbell Skull on Normal or harder.
- Skulltaker Halo 3: Famine
Halo 3: Find and claim the Famine Skull on Normal or harder.
- Skulltaker Halo 3: Fog
Halo 3: Find and claim the Fog Skull on Normal or harder.
- Skulltaker Halo 3: Catch
Halo 3: Find and claim the Catch Skull on Normal or harder.
- Skulltaker Halo 3: Tough Luck
Halo 3: Find and claim the Tough Luck Skull on Normal or harder.
- Skulltaker Halo 3: Grunt Birthday Party
Halo 3: Find and claim the Grunt Birthday Party Skull on Normal or harder.
- Skulltaker Halo 3: Iron
Halo 3: Find and claim the Iron Skull on Normal or harder.
- Skulltaker Halo 3: Black Eye
Halo 3: Find and claim the Black Eye Skull on Normal or harder.
- Refuge
Halo 3: Complete The Ark.
- Waypoint
Halo 3: Beat the par time on The Ark.
- Skulltaker Halo 3: Blind
Halo 3: Find and claim the Blind Skull on Normal or harder.
- Cleansing
Halo 3: Complete Floodgate.
- Dambuster
Halo 3: Beat the par time on Floodgate.
- Assault
Halo 3: Complete The Storm.
- Lightning Strike
Halo 3: Beat the par time on The Storm.
- The Road
Halo 3: Complete Tsavo Highway.
- Highway Robbery
Halo 3: Beat the par time on Tsavo Highway.
- Holdout
Halo 3: Complete Crow's Nest.
- Time Shift
Halo 3: Beat the par time on Crow's Nest.
- Can't Keep Him Down
Halo 3: Fight alongside and listen to The Man. The Legend. Chips Dubbo.
- Landfall
Halo 3: Complete Sierra 117.
- Speedy One One Seven
Halo 3: Beat the par time on Sierra 117.
- Primate
Halo 3: Find your first missing links.
- Guerilla
Halo 3: Beat the par score on Sierra 117.
- Cavalier
Halo 3: Beat the par score on Tsavo Highway.
- Askar
Halo 3: Beat the par score on The Storm.
- Exterminator
Halo 3: Beat the par score on Floodgate.
- Ranger
Halo 3: Beat the par score on The Ark.
- Vanguard
Halo 3: Beat the par score on The Covenant.
- Orpheus
Halo 3: Beat the par score on Cortana.
- Torchbearer
Halo 3: Beat the par score on Halo.
- Better With Age
Halo 3: Beat the par score on every Halo 3 level.
- Rising Waters
Halo 3: Activate Terminal 1 on The Ark.
- Inundation
Halo 3: Activate Terminal 2 on The Ark.
- Before the Fire
Halo 3: Activate Terminal 3 on The Ark.
- Tipping Point
Halo 3: Activate Terminal 4 on The Covenant.
- Unto Dust
Halo 3: Activate Terminal 5 on The Covenant.
- Babbling Dead
Halo 3: Activate Terminal 6 on The Covenant.
- Sword and Shield
Halo 3: Activate Terminal 7 on Halo.
- The Coin's Fault
Halo 3: Activate Cortana's Terminal on Cortana.
- Whispers Across the Galaxy
Halo 3: View the communique from Mendicant Bias.
- Prophet's Bane
Halo 3: Complete every level of the game on Normal difficulty.
- With Your Shield or On It
Halo 3: Complete every level of the game on Heroic difficulty.
- Finished the Fight
Halo 3: Complete every level of the game on Legendary difficulty.
- Begins with a Single Step
Halo 3: On Tsavo Highway, complete the level without entering a vehicle.
- Who Needs Them?
Halo 3: On The Ark, complete the level without entering a vehicle on Legendary.
- Phantom Hunter
Halo 3: Destroy 3 total Phantoms on The Covenant.
- Annual
Halo 3: Complete Halo on 4-player Legendary co-op, with Iron Skull, and everyone in Ghosts.
- Dirge of Madrigal
Halo 3: Trigger the hidden music cue in Halo 3.
- Haplorrhini
Halo 3: Find a lonely missing link.
- Heading to his Destiny
Halo 3: Destined for greatness.
- Sounds Familiar
Halo 3: This stuff is your history!
- Hippo Hero
Halo 3: Who DARED to discard this brave animal?
- Milk Carton
Halo 3: Find the poster of the missing man.
- Cool Story Bro
Halo 3: Listen to the story of the Final Grunt.
- Man on the Moon
Halo 3: He's watching you.
- Elder Signs
Halo 3: View 2 different sigils on Valhalla.
- Third Time's A Charm
Halo 3: Play a game of Halo 3 on the 25th of any month.
- Devastating
Halo 3: Complete all Halo 3 Legendary campaign missions in under 3 hours.
- Mind the Gap
Halo 3: 4 vehicles, 1 gap on Legendary using Cowbell, Catch, Thunderstorm, Mythic, and Tough Luck.
- Missing Link
Halo 3: Watching. Waiting. Plotting.
- A Preference for Pain
Halo 3: Complete the Halo 3 LASO Campaign playlist.
- Aficiando
Halo 3: Complete three Halo 3 playlists.
- Boot Camp Hero
Halo 3: Complete a Halo 3 playlist.
- King of the Crows
Halo 3: Beat the par score on Crow's Nest.
- No Stone Unturned
Halo 3: Activate all Halo 3 Terminals.
- Citadel Skull
Halo 3: Find the hidden Skull on the Citadel multiplayer map.
- Brainpan
Halo 3: Find all the hidden multiplayer Skulls.
- World Traveler
Halo 3: Complete a match on at least 8 different multiplayer maps.
- Just Browsing
Halo 3: Complete a match on at least 4 different game types in multiplayer.