The Battlefield team has done a good job of maintaining radio silence regarding upcoming expansions to BF3. However, at an event last night, details were provided about several incoming additions to the game. The first, an expansion pack dubbed Close Quarters, will arrive in June. This one focuses on "tight indoor environments" and promises lots of "high definition destruction."
According to Eurogamer, the first expansion will feature four new levels and 10 weapons. If you're looking for fresh vehicles, you'll have to wait for the fall, when the Armored Kill expansion pack is due to arrive. This one comes with new tanks, ATVs, and mobile artillery. It also includes the "biggest map in Battlefield history." The Close Quarters pack is meant for 2-16 players, but it seems Armored Kill is being designed for much bigger crowds.
During the winter, a fourth expansion pack will be released. All we know about this one is the name, End Game, which seems like it could be the final chapter for BF3. Screenshots and a gameplay trailer for the Close Quarters release are due out next week, though.