A quick note before we get to any achievement talk. To get the 'Jaws' achievement in Battlefield 3, you'll need the Back to Karkand DLC. There are two ways to get it, though. Either you payed for it, or you got it for free because you pre-ordered the game.
Okay, in order to get 'Jaws', you have to go for a dip. Hop into a game of Conquest on the map "Gulf of Oman". Behind the hotel near the southwest area of the map, there's a pool. Go swimming for a bit, and you'll earn the easiest achievement in achievement history.
- PlayStation 3: Bronze Trophy
- Xbox 360: 20G