It's Begin's second stint with the Flames. He played for Calgary from 1997 to 2003 after being drafted by the club 40th overall in 1996.
The 34-year-old entered camp this year on a professional tryout after taking last season off due to a hip injury.
He played only two NHL games in 2010-11 for the Nashville Predators, but played 77 games the season prior for the Boston Bruis. He finished with five goals and 14 points during the 2009-10 campaign.
Flames general manager Jay Feaster says the club hopes to use Begin on special teams units.
"Steve worked very hard during camp and demonstrated that he is an effective player killing penalties, making life difficult for opposing players and providing a spark and positive energy when needed," said Feaster in a statement.