Primordial Vaults are some of the toughest challenges you’ll come across in Borderlands 4. Each Vault is hidden deep within the regions of Kairos, and unlocking them isn’t as simple as walking up to the door. First, you’ll need to track down three Vault Key Fragments in each area before you can open the portal and face what’s inside. These Vaults test your combat skills with multiple arenas, a tough Guardian boss, and plenty of loot waiting at the end. This guide will show you the location of every Vault and all the fragments you’ll need to open them.
All Primordial Vault Locations
Primordial Vaults are one of the tougher new activities in Borderlands 4, and you’ll find one Vault in each region of Kairos: The Fadefields, Carcadia Burn, and Terminus Range. To open them up and claim the loot inside, you’ll first need to collect three Vault Key Fragments scattered around each area.
Here’s how it works: start by looking for Order SILOs on your map. When you reach one, hack the console with Ech0-4. This unlocks fast travel to that spot and also highlights a nearby area where a Vault Key Fragment is hidden. From there, use the communications balloon grapple point to pull yourself up, then glide straight to the marked location.
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Primordial Vault #1: Arch of Inceptus
Found in Dissected Plateau. Once you’ve collected all three Fadefields fragments, a stone lever appears. Use it to insert the Fadefields Vault Key, and a purple portal will open. Step through to enter the Vault, where you’ll get a side quest and then fight through three arenas before facing the Vault Guardian boss.
Vault Fragment #1: Coastal Bonescape
The Stockroom SILO can be found in the Coastal Bonescape area of The Fadefields. Once you hack it, you’ll unlock a fast travel point and get directed to a Vault Key Fragment in the Stillshore. From there, just head west toward the shoreline until you reach Stillshore. Look around the houses, and you’ll spot the fragment sitting on a wooden box outside one of them.
Vault Fragment #2: The Howl
This one is up a mountain. Approach from the north side of the icon and climb the rocks. The fragment is on a plateau halfway up, not at the very top.
Vault Fragment #3: Idolator’s Noose
Check the side of a building here. You’ll see a grate you can pull open, which leads to a hidden room underneath. The fragment is inside.
Primordial Vault #2: Arch of Radix
Found in Grindstone of the Worthy. After grabbing all three Carcadia Burn fragments, the lever and Vault Key slot appear. Activate it, step through the purple portal, and you’ll enter the Vault. Inside is a side quest, three combat arenas, and the Vault Guardian boss.
Vault Fragment #1: Lopside
The Rustic Hurl SILO is in the Grindstone of the Worthy area of Carcadia Burn. Once you’ve unlocked it, fast travel to the Makeshift Chalet safehouse in Lopside (or just head to Lopside if you’re nearby). From the safehouse, go south, and you’ll find the Vault Key Fragment on top of the gas station roof.
Vault Fragment #2: Tonnage Peel
The Site Unseen SILO and its Vault Key Fragment are in the Tonnage Peel region of Carcadia Burn. Head over to the Wreck of the Last Great Hope and go inside. Look for a vent door you can grapple open, and the fragment will be waiting inside.
Vault Fragment #3: Ruined Sumplands
The Judgement’s Lapse SILO and its Vault Key Fragment are in the Ruined Sumplands area of Carcadia Burn. Look for the point of interest called Hull’s Handbasket along the water’s edge. From there, drop down the small cliff nearby, and you’ll spot the fragment waiting for you.
Primordial Vault #3: Arch of Origo
Located in The Low Leys. Collect all three Terminus Range fragments, then use the lever and Vault Key to open the purple portal. Inside, you’ll find a side quest, three arenas, and the Vault Guardian boss.
Vault Fragment #1: Cuspid Climb
A bit tricky. The fragment is on a plateau partway up a mountain. To get there, start about 150 meters west of the icon at the top of some cliffs, then glide across to the ledge. There’s a tunnel there that leads to the fragment.
Vault Fragment #2: The Low Leys
Climb up the rocky path made of small rocks near the road. At the top, use the grappling point to pull yourself onto the ledge with the fragment.
Vault Fragment #3: Windspear
The last Vault Key Fragment is found at the edge of the Windspear region in Terminus Range, close to Checkpoint Taupe and Vestal Garrison. Head inside the building, there and make your way up to the second-floor office area, where you’ll find the fragment.
