Here is the full list of all 34 Battlefield 3 achievements. It takes around 100-120 hours to unlock all of the achievements on Windows.
Rank 45 achieved!
Received one of each ribbon in the game
Received all 4 support efficiency ribbons
Unlocked all xbow parts
Received all 3 vehicle warfare ribbons
Took a swim in the Oman Hotel swimming pool
Won a round in Conquest Domination
Got 10 kills with each of the ten Back to Karkand weapons
Got 10 kills with all ten CQ weapons
Received all 4 weapon efficiency ribbons
Killed an enemy after successfully paradropping a vehicle
Won one round of Tank Superiority
Destroyed an enemy vehicle using the xbow
Without dying, got a kill with xbow, primary weapon, and hand grenade
Found the secret reptile
Without dying, got a kill with a Carbine, Pistol and Rocket Launcher
Completed a round of Gun Master
Fell over the edge on Ziba Tower
Picked up 50 weapons in Scavenger mode
Got 10 kills each with Tank destroyers and Mobile Artilleries
Took your first enemy Dog Tag
MVP in a ranked match
Got a kill with each of the following vehicles: the BTR-90, DPV and F-35.
Got a kill with the following weapons in a single life: Assault Rifle, Jet, Tank
Got one kill with the Quad bike
Destroyed the Gunship
Got one kill with the Gunship
3rd MVP in a ranked match
Destroyed an air vehicle using the AA jeeps
2nd MVP in a ranked match
Transported a flag carrier in an air vehicle in CTF
Got a kill from the passenger position on a motorcycle
Captured one flag while playing CTF
Got a kill with the skid loader