This is only single player.
It is a short campaign. A game like Crysis 2 and Vanquish took time between 8-11 hours. This one maybe took me 5. Perhaps a harder difficulty would have proven to be longer but for me. That was the biggest disappointment. But for those of you looking to see what the frostbit 2 engine is capable of, you will be impressed. Battlefield 3 is a very nice looking game, and the guns are balanced. You can't just play the game through with a really cheep gun, provided I found they gave you a lot of ammo in the game, but that's just me.
In terms of story, Battlefield 3 has some good narrative but it is predictable. There was no unique part of the game that made you think, "wow that is something new". It was all what you would except from a serious modern war game. And just throwing that out there the game is serious. There is really no part that will make you laugh besides if you get a funny shot in the game or something.
Overall I am rating the campaign in Battlefield 3 a 6.5 It is standard but not broken. I was excepting maybe too much from the campaign after playing Crysis 2, and maybe I was expecting too much from the engine after seeing the Cry Engine 3. Wait for this game to go to the cheep bin, or rent it if you only want to play the single player. I would have wasted money in that regards.
P.S. This is only single player. My friend is loving multi player thus far