WASHINGTON — Southwest Airlines Co., the discount carrier with the ‘‘Bags Fly Free’’ slogan, is forecasting $100 million in annual revenue from fee changes that will include the first charges for no-shows on flights and for premium boarding ­positions.

The new fees and increases in existing charges will start in the first quarter of next year, chief commercial officer Bob Jordan said Friday. Dallas-based Southwest expects to boost revenue by $1.1 billion in 2013.

The fees mark a departure from Southwest’s reputation as a no-frills carrier that bucked the rest of the industry by letting ­passengers check two bags for free and change flights without penalty. The no-show fee would be levied on passengers who don’t cancel tickets before a flight.

‘‘This one is pretty industry standard,’’ chief executive Gary Kelly said.