All DC Universe Online Heroes and Villains may create their own bases. Legendary members and owners of the Lair System DLC will receive two lair themes: "Gothic" and "Deco", as well as a theme for a smaller, limited "Dive" Hideout, which can be retrieved from your base Dispenser. Free members and non Lair System DLC owners will only receive the Dive theme. Look for "Home is Where Your Base Is" in your Mission Journal to receive your themes; continue the mission to receive one deed, which can be used for placing a base at an in-game address of your choice. The mission is granted at level 12 or higher. Other themes are available through the In-game Marketplace and will be available for use after consuming them; players will need to relocate their base in order to change themes. Please be aware there is a one hour lockout period after changing your Lair theme. Characters may own no more than four lairs and will no longer be able to purchase lair deeds from the marketplace upon reaching that limit.

Each base comes equipped with a Mainframe and a Dispenser which can be accessed inside the base. Players can unlock access to upgrades and temporary boosts by activating the Mainframe's Generator Power Cells; these unlocked boosts and abilities will create mods and devices which can be acquired in your Dispenser and equipped on your character. Each time you raise the rank of a mod or trinket with your mainframe, that new rank item may be located in your dispenser. Please be aware you may carry no more than four of the same mod or device; also be wary of the level of the device before dispensing it. Players can also set permissions through their Mainframe to allow friends and league mates to enter and help decorate their lair.

In addition, players are able to customize their base in many different ways using the Base Decoration Mode. Accessed via the control panel located near the entrance of your base, Decoration Mode is the place for arranging items throughout the base, customizing the colors of certain areas of the base, selecting your character's emblem to be displayed on a wall plaque, and renaming the base. Special characters (such as %, &, or #) can't be used when naming bases and the name can't exceed more than two separate words; Super Fortress would be acceptable, but not Super Duper Fortress. Players can customize their base by adding items found throughout DC Universe Online, everything from couches, beds, and TVs to functioning equipment, like a Bank or R&D Station. Functional furniture, such as the bank and R&D Station, are amenities; each base may only hold four amenities, regardless of which the player chooses to use. Players with multiple bases may place four amenities in each base. Although friends may access amenities, only the lair owner will have access to the dispenser.