Citadel Skull

Citadel Skull Effect: The Citadel Skull has no effect.
Citadel Skull Location:
The Citadel Skull can be found on the Mythic map, “Citadel”. It is located above a wall with blue triangles on it in the ceiling (shown in photos below). In forge mode, it can be accessed easily if working with two people. Use one player to create a makeshift elevator/floating platform with a wall. Lift the other player into the ceiling to grab the skull.

Longshore Skull

Longshore Skull Effect: The Longshore Skull has No Effect.
Longshore Skull Location:
The Longshore Skull can be found on the Mythic map, “Longshore”. The Longshore Skull is located behind two air vents above the water in an area out of reach of regular players. To get to the Longshore Skull, you must be in Forge, and use the monitor to fly on top of the air vents to grab the skull.
You can see photos and a Longshore skull location video below=============================^

Hint 1: The Longshore Skull is located back on these Air Ducts.

Herecit Skull

Heretic Skull Effect: The Effect of the Heretic Skull is unknown. There may be no effect whatsoever.
Heretic Skull Location:
The Heretic Skull can be found on the Mythic map, “Heretic”. To get the heretic Skull, enter Heretic in forge mode, then fly towards the top of the Blue base and the skull is located in the vent-like ducts.
You can see photos and a Heretic skull location video below===============================^

Hint 1: Heretic from the Halo 3 Mythic Maps. The Location of the skull is highlighted above.

Commando Armor

There have been reports of bugs with the Elite “Commando” Armor being unlocked from some players.  For some reason, pieces of the armor set are not being unlocked, and we do expect a fix from Bugnie sooner or later.  To unlock the armor permutation, here is what has to be done:

• To unlock the “Commando” Body, you need to complete the “Triple Kill” achievement.
• To unlock the “Commando” Shoulders, you need to complete the “Killing Frenzy” achievement.
• To unlock the “Commando” Helmet, you need to complete the “Overkill” achievement.

Ascetic Armor

You’ll need to grab a few achievements in Halo 3 before acquiring the full Ascetic Armor set for the Elite Player model:

• For the “Ascetic” Body, you need to unlock the “Up Close and Personal” achievement.
• For the “Ascetic” Shoulders, you need to unlock the “Overkill” achievement.
• For the “Ascetic” Helmet, you need to unlock the “Steppin’ Razor” achievement.

Flight Armor

The “Flight Armor” is from the Jetpack Elites from Halo 2, and is now an unlockable armor set in Halo 3.  In order to unlock it, you will need to complete a few different tasks in Campaign mode of Halo 3:

• For the “Flight” Body, you will need to beat “Tsavo Highway” on either Heroic, or Legendary Difficulty Setting.
• For the “Flight” Shoulders, you will need to beat “The Ark” on either Heroic, or Legendary Difficulty Setting.
• For the “Flight” Helmet, you will need to beat Halo 3 or either Heroic or Legendary difficulty settings.

Assault Armor

The “Assault Armor” is another default armor set for the Elite player model, and does not have to be unlocked.  You may recognize this armor set from the “Heretics” who wore it in Halo 2.  It features a slick helmet that produces some really great reflection effects.

Combat Armor

The  “Combat Armor” is the default Armor set for elites, and the most recognizable (as it is the standard issue elite Armor from the Halo Trilogy).  This armor set is unlocked and ready for use by default, and can be accessed by switching your player’s model to “Elite”.

Recon Armor

Looks like Bungie wanted something to let them stand out among fellow gamers in Halo 3. There is a set of Armor (Recon), and a Helmet (Flaming Hayabusa) which can only be worn by Bungie Team members and select community members.
Perhaps later on, Bungie will make this content accessible to all, or maybe even give the armor away in contests/competitions.
We’ll have to wait and find out for the time being.

Rogue Armor

You’ll need to play online in matchmaking quite a bit to unlock the “Rogue Helmet” in Halo 3.  In order to unlock this armor piece, you need to get the “Spartan Officer” achievement (reach the spartan Officer ranks online).  It’s been dubbed the “Ninja Turtle” helmet by some.

Mark V Armor

Remember the classic “MARK V” armor from the original “Halo: Combat Evolved”? Well, you can bring back the MARK V Helmet by unlocking the “UNSC Spartan” achievement. Reach a rank in matchmaking of Sergeant Online, and the helmet is yours!

ODST Armor

The ODST (Orbital Drop Shock Troopers) Helmet is a standalone piece of unlockable armor.  It does not have shoulders or a body piece, but you can mix and match with other sets.  To get this Helmet, you’ll need to become a “Spartan Graduate”.  Simply reach the rank of Private in Xbox Live matchmaking to unlock the ODST Helmet.

Scout Armor

Unlocking the Scout Armor permutation in Halo 3 requires Unlocking several achievements in the game:

• To unlock the Scout “Body” Armor, unlock the “Too Close to the Sun” achievement.
• To unlock the Scout “Shoulders” Armor, unlock the “Mongoose Mowdown” achievement.
• To unlock the Scout “Helmet” Armor, unlock the “Used Car Salesman” achievement.

Marathon (Security) Armor

You unlock the Security Armor in Halo 3 by getting Gamerscore in the game (ie: unlock achievements). To get the Shoulder Armor, you will need to rack up a whopping 700-850 GS (it seems to vary for some reason).
Note: There is a known glitch in the game that will not allow players to unlock the Security Shoulders sometimes.
This might be one of the last pieces of Armor you unlock in the game, as it requires all of the achievements in Halo 3 in order to unlock it. That’s right. You need 1000/1000 GS on Halo 3 to unlock the Security Helmet.

Flaming Helmets

As if keeping the Recon Armor for themselves wasn’t enough, Bungie went ahead and added one of the coolest things we’ve ever seen, and then restricted it to Bungie Team members only. The Flaming Helmet is identical to a regular helmet, only it’s… well… flaming.
We’ve seen some awesome photos of the helmet in action on Bungie Team members profile pages (the one above was taken from Billy77Bones). We’d love to see some downloadable content soon so that we can get our hands on these gems, but we’re not holding our breath.
Then again… The flames are a dead giveaway when you’re invisible, and probably draw attention to you in lots of other situations as well. Is that trade off worth wearing a Flaming Helmet?
Answer: Definitely.
Bungie members activate the helmet’s flaming trait by using the “Bungie” chestplate, which looks all but identical to the E.O.D. Armour chestplate. This allows any helmet to become “Flaming.” (Thanks to Grant for the heads up)

Hayabusa Armor

Perhaps the most popular Halo 3 Armor variation on Xbox Live, the Hayabusa Armor (or “Ninja Armor” as many call it) is one of the trickier armors to unlock. To get the full set, you will need to unlock every Skull in the game.

• To get the Hayabusa Body, unlock 5 Skulls.
• To get the Hayabusa Shoulders, unlock 9 Skulls.
• To get the Hayabusa Helmet, unlock all of the skulls.
• To unlock the Hayabusa Sword Add-on (attaches to back of Body Armor), you’ll need to unlock all of the achievements in Halo 3 (1000/1000 GS).

EOD Armor

The EOD Armor set in Halo 3 is a bit more difficult to get than armor such as the EVA set. Rather than beating campaign missions on Normal, or Heroic, you will need to beat them on the Legendary difficulty.

• To unlock the EOD “Body”, beat “Tsavo Highway” on Legendary.
• To unlock the EOD “Shoulders”, beat “The Ark” on Legendary.
• To unlock the EOD “Helmet”, beat the Campaign on Legendary.

EVA Armor

To unlock the EVA Armor in Halo 3, you will need to complete a few different tasks.

• To unlock the EVA “Body”, you will need to complete “Tsavo Highway” in Campaign mode on either Normal, Heroic, or Legendary.
• To unlock the EVA “Shoulders”, you need to complete “The Ark” in Campaign mode on either Normal, Heroic, or Legendary.
• To unlock the EVA “Helmet”, you will need to complete the Campaign on either Normal, Heroic, or Legendary.

You can knock this whole set out in one run by simply finishing the game in Normal, Heroic, or Legendary difficulty mode.

CQB Armor

 

The C.Q.B Armor Permutation in Halo 3 is unlocked by default. This armor variation features a knife on the “Body” section of the armor (not the blade on the back of the armor, which is unlocked after reaching 1000/1000 GS).

Mark VI Armor

 

The MARK VI Armor is the default armor assigned in Halo 3, and is not unlocked. This is the same armor that you play with in the Campaign mode of the game. It is the upgraded version of the MARK V Armor from the Original, “Halo: Combat Evolved”.