Below you will find images of all Halo 4 armor unlocks followed by the requirements on how to achieve them, if new armor is added to this list then I will update them as and when I know about them.

Spartan Armor Sets

Below are the requirements needed to unlock each armor set, forearms, legs and visors.

 

Unlocked at SR ranks

Recruit: Starting Armor
Warrior: Unlocked at rank SR8
Air Assault: Unlocked at rank SR13
Soldier: Unlocked at rank SR15
Aviator: Unlocked at rank SR17
Defender: Unlocked at rank SR24
Recon: Unlocked at rank SR26
EVA: Unlocked at rank SR27
War Master: Unlocked at rank SR37
Scout: Unlocked at rank SR38
Orbital: Unlocked at rank SR41
Infiltrator: Unlocked at rank SR42
Hazop: Unlocked at rank SR43
EOD: Unlocked at rank SR45
Oceanic: Unlocked at rank SR47
Enforcer: Unlocked at rank SR50

 

Commendation Armor Unlocks

Air Assault VERG: Vehicle Mastery
Aviator Bond: Wheelman Mastery
C.I.O.: Spartan Slayer Mastery
Commando: Dominion Victory Master
Commando FRCT: Flood Victory Mastery
Defender CTRL: Bullet in the Brain Master
Enforcer Tribal: Turret Mastery
EOD SHDW: Regicide Victory Mastery
EVA BRCH: Hail of Death Master
Gungnir: Slayer Victory Master
Infiltrator TRAC: Multikill Master
Mark VI: Complete the campaign on Legendary (Solo or Co-op)
Orbital AEON: Covenant Destroyer
Protector: UNSC Loadout Master
Protector Drift: Weapon Mastery
Ranger: Combat Opportunity Master
Ranger STRK: Protector Mastery
Recon Surge: Covenant Loadout Master
Scout APEX: Oddball Victory Mastery
Soldier ZNTH: Killing Spree Master
Vanguard: Forerunner Destroyer Master
Vanguard CNVG: Flag Victory Mastery
Venator: Assassin Master
Venator Raptor: Backstab Mastery
War Master PRML: King of the Hill Victory Master
Warrior MTRX: Forerunner Loadout Master

 

Forearm Unlocks

Contoured: Unlocked at rank SR39
GV-09 Locking: Unlocked at rank SR22
Inner-plated: Unlocked at rank SR30
Outer-plated: Unlocked at rank SR34
Recruit: Default
Twin-plated AEON: Close Quarters: Master Commendation
Twin-plated: Unlocked at rank SR9

 

Leg Unlocks

Contoured: Unlocked at rank SR40
Contoured leg CHVR: Payback Mastery
Contoured SHRD: Payback: Master Commendation
LG-50 Bulk: Unlocked at rank SR23
Outer-plated: Unlocked at rank SR31
Recruit TIGR: Exterminator: Master Commendation
Recruit: Default
RG-63 Counter: Unlocked at rank SR10
XG-89 Narrow: Unlocked at rank SR35

 

Visor unlocks

Blindside: Avenger Master Commendation
Blue/Orange: Wetwork Specialization
Cyan: From the Brink: Master Commendation
Frost: Unlocked at rank SR29
Gold: Operator Specialization
Legendary: Complete the campaign on Legendary (Solo or Co-op)
Midnight: Unlocked at rank SR46
Orange/Purple: Operator Specialization
Orange/Green: PathFinder Specialization
Pink/Purple/Blue: Engineer Specialization
Purple: Tracker Specialization
Recruit: Default
Red/Orange/Silver: Rogue Specialization
Silver/Blue: Pioneer Specialization
Solar: Unlocked at rank SR20
Sunspot: Assistant: Master Commendation
Verdant: Splatter: Master Commendation
Yellow/Green: Stalker Specialization