The deal, which was first reported by ESPN Deportes, is pending a physical. The Reds have made no formal announcement.
Exact terms of the contract are not known, but Pena is expected to get a raise from the $865,000 he made last season with Detroit.
Pena, who will turn 32 in January, is a native of Havana, Cuba. He batted .297 with four home runs and 22 RBIs over 71 games last season for the Tigers.
In the big leagues since 2005, Pena has also played for the Braves and Royals. Lifetime, he is batting .258 with a .292 on-base percentage, 18 homers and 120 RBIs over 406 Major League games.
Cincinnati currently has two catchers under club control on its 40-man roster. Veteran Ryan Hanigan is headed for his third year of arbitration eligibility, and Devin Mesoraco just