Fallout 4: How Do You Get Into Vault 81?

Vault 81 is one of the other Vaults you can access in the Commonwealth after leaving Vault 111. However, there is a small quest that requires you to find three Fusion Cores before Overseer McNamara allows you to enter and roam free in the Vault.

Vault 81 is an active and well-maintained Vault-Tec nuclear shelter on the far western edge of the World Map in Fallout 4, just northwest of Diamond City. Upon encountering the Vault, you’ll first have a conversation with the Overseer, who will demand that you turn over three Fusion Cores before they open the Vault Door for you and your companion.

The trick here is knowing where to find these Fusion Cores. Although numerous, they are unlimited in quantity in the Commonwealth. Fortunately, there are locations from which you can easily obtain these to exchange for access to Vault 81.

Mole Rat Den in Red Rocket

Credit: Bethesda

This spot deserves the first place in this guide because it’s tough to miss. The Mole Rat den is just beneath the Red Rocket station, which is across the bridge from Sanctuary Hills. This is the first location you add to your Fast Travel menu right after you exit Vault 111.

To find the Den, go down the small slope immediately in front of the Red Rocket building. A clump of tyres mark it, and it has a small entrance you can squeeze through.

First, you’ll need to kill the Mole Rats, including a Glowing variant waiting in the right-side chamber. Beyond this chamber is the damaged safe where the Fusion Core is stored.

USAF Satellite Station Olivia

Credit: Bethesda

USAF Satellite Station Olivia is a relay station located just east of Sanctuary Hills. You’ll initially find this location infested with Raiders, whom you’ll need to dispatch before you can enter and explore the station safely. Watch out for their leader, Ack-Ack—he carries a minigun, but you can easily dispatch him with well-aimed VATS attacks.

You’ll need to enter the main building and descend to the basement to find the Fusion Core. It is embedded in the generator in the middle of the room.

Super Duper Mart

Credit: Bethesda

You’ll most likely encounter the Super Duper Mart at this point in your playthrough if you’ve joined the Minutemen right after rescuing Preston Garvey and the Quincy survivors in Concord. A group of settlers should have asked you to clear the Mart of feral ghouls as part of the Ghoul Problem quest.

When you enter the Super Duper Mart, go all the way to the back, where you can find a generator. The Fusion Core will provide the power.

It may be daunting to begin this quest in Fallout 4, but these locations are easily accessed and may even be on your map already after certain quests. After giving McNamara her three Fusion Cores, you’ll enter Vault 81, where you can find some quests for loot and additional experience.