Quote Originally Posted by LaylaTsarra View Post
You can do multiplayer beginning with Satasha Baby at story level 15. You don't need to be in Heavensward to do it.
Quote Originally Posted by ohmRICE View Post
The multiplayer aspect isn't locked until you complete the story though. You can actually play along side your friends while going through the story together, you can still chat with other players (though you'll not be able to join in when they start talking about the most recent story addition), and partake in your normal multiplayer activities.

In fact, you can't progress through the story without playing with other people! There's no soloing Sastasha!
After I unlock that first dungeon, no matter how much I play it or how far I level I can't do anything but that single dungeon unless I do hours more of the story.