An access key (sometimes called "key code" or simply "key") is a 25-digit alphanumeric code used to create an account or to add features to an existing account. It has to be entered during the registration of the game account in order to be able to play online. Access keys can be bought either online or at a store stocking a Guild Wars game product.

The access key also defines which geographic server a player initially connects to, however, players may change their home territories later, during setup.