Sign into Moshi Monsters online at MoshiMonsters.com. Click the Log In link near the top right of the home page, and then sign in using a previously established owner name and password.
For first-time users, click the Get a Monster Now link on the login page or the Play Now link near the center of the home page to establish an account. Complete the steps, which include choosing a monster, choosing a monster color and creating a username and password. Gender and age are also requested.
The basic version of Moshi Monsters is free to play, as of 2015. A paid membership is available and includes additional features, such as the ability to change the character's color and access to member-only games.