Did you pre-order Battlefield 3 via Origin, Amazon, or any other service that supports pre-loading? Then starting on the 21st you'll be able to pre-load your copy of Battlefield 3. If you live in the states, that gives you a four day head start on those who are buying the game on release day (October 25). If you don't live in America, your release date can be found below:

October 25, 2011
USA, Canada

October 27, 2011
Denmark, Finland, Netherlands, Germany, France, Spain, Norway, Sweden, Australia

October 28, 2011
UK, Poland, Czech Republic, Italy

What is pre-loading? Pre-loading will allow you to download Battlefield 3 and once it is released in your region, you can immediately start playing. No need to drive to the store, wait inline, or spend time installing the game. This option is available to those who pre-ordered a digital copy of Battlefield 3.