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 because of a hip injury.
Flames general manager Jay Feaster says the club hopes to use Begin on special teams.
"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," Feaster said in a statement.