* Q2 EBITDA 434 mln euros vs 475 mln euros expected
* Keeps 2012 outlook
BRUSSELS, July 27 (Reuters) - Belgium's dominant telecoms operator Belgacom missed market expectations with a 15 percent drop in second-quarter core profits, hit by its offering of free soccer matches to its television customers.
Belgacom said the result at its consumer unit was also affected by regulation and an adjustment to take into account a change in the Belgian telecom law.
At the group level, core profit in the second quarter fell 15.2 percent to 434 million euros ($533.82 million), below the 475 million expected in a Reuters poll of seven analysts.
The group reiterated that it expects its 2012 revenues to fall by about 1 percent in 2012, with core profit declining between 5 and six percent.
The decline is based on the group's view that it will get lower revenue from traditional phone calls -- both mobile and fixed -- with some support from mobile data growth, due to the increasing number of smartphones and tablets.
Belgacom, which competes with Mobistar and KPN's BASE in the Belgian mobile market, used to show top Belgian soccer league matches on a pay-per-view basis, a major draw to its TV services, but lost those rights to cable rivals Telenet and Voo in 2011.
The group has since decided to show selected matches free of charge. ($1 = 0.8130 euros) (Reporting By Robert-Jan Bartunek; editing by Philip Blenkinsop)