Q&A for How to Turn Your Sim Into a Vampire

You will need an expansion pack in order to turn your Sim into a vampire. The Supernatural expansion pack is the best for this, as you can turn your Sim into a vampire on the Create-a-Sim mode. The Late Night expansion pack will also work, but you cannot make your Sim into a vampire on Create-a-Sim; you will have to find one first.

You will first have to change your fairy Sim to a normal Sim using the potent cure elixir or the "ask forsake the fae" action with a significant other, then follow the steps in this tutorial.

Hold down Ctrl-Shift-C and type "TestingCheatsEnabled true". Shift-click your mailbox and press "Make me some friends". Eventually there will be a vampire.

Unfortunately, no. None of the Sims games include vampires as part of the base game. You might be able to download base-game-compatible custom content to make your Sims look like vampires, but that would be purely cosmetic and they won't have any of the abilities or needs that vampires do.