Bah started the season 2007 with KPV, but moved to Helsinki when Veikkausliiga club HJK took him on a season-long loan. He made his debut in a UEFA Cup match against FC Etzella of Luxembourg, and scored a goal. Later the capital club signed him on a three-year contract. In 2009 Bah was one of the most important features in the Finnish title winning side HJK, scoring eight goals and assisting eight times in 25 league games. In 2010, Bah continued showing his importance for HJK Helsinki, both in the Finnish league and the Champions League qualifications. Due to his good performances he was given a two-year extension to his current contract on 2 September 2010. His new contract ran until 2012.