Folowing its posting last night, we now have details for the Hidden Ability Unova Starters in Europe and North America. Serperior begins today with the code POKEMON497 from the official site. 
Reckless Emboar will begin from January 29th 2015 also from a code from the official site and Shell Armor Samurott will run from February 5th 2015 through a code from the Pokémon Trainer Club Newsletter. 
All three promotions end on November 30th. It’s not currently clear if these promotions will match the serial code Japan had for them earlier this month like the Serperior has, but when we know we shall post the password and that they are active so keep checking back.

Source: Serebii