All dogtags mentioned below are now available to buy as part of the Spec-Act addon pack. Searchword “dogtags” in the Origin Store should work.
Watch the Act of Valor trailer and get five cool tags
(Note: You need to watch the whole clip through).
Get a limited dogtag from Alienware Arena
(Note: You need to create an account and login, then redeem the key in Origin for this one).
Dr Pepper bottles
For those who live in the US of A, there’s also five dogtags (pictured below) to be grabbed from Dr Pepper bottles. Thanks to 123 for the tip in the comments!
Know any more ways to get “exclusive” unlocks for Battlefield 3? Please comment below!