Assassin's Creed 3 will not have a multiplayer beta according to Ubisoft. The developer, who held a beta for previous AC games, Assassin's Creed: Brotherhood and Assassin's Creed: Revelations stated that, while getting community feedback through beta testing is helpful, the process takes time that they'd rather spend adding elements to the game.
"We’d need to polish a version, submit it to the platform holders and support it when it’s out," said Ubisoft Annecy multiplayer game director Damien Kieken. "And all the time put into the beta doesn’t go into the final game."
And there you have it. Assassin's Creed 3 is coming to the Xbox 360, PlayStation 3, and PC on October 30. While you won't get to play it until then, you can check out its gorgeous new graphics in the latest Assassin's Creed 3 graphics trailer.