Mujangi Bia emigrated with his family from DR Congo to Zellik, Belgium as a young child. He began his football career on the books of the Brussels-based club Union Saint-Gilloise, before being spotted by Anderlecht. Although one of their academy's most promising players, he was released by the club after being caught stealing from them. After some months without a club, he joined Charleroi where he made his professional debut on 17 December 2006 in 0–1 defeat at Zulte Waregem, the first of three appearances that season. He scored his first senior goals the following season, before 2008–09 saw his most appearances yet as he played 28 league games. The midfielder joined English Premier League club Wolverhampton Wanderers on loan on 21 January 2010 for the remainder of the 2009–10 season. He made his Premier League debut as a substitute in a 2–2 draw at Hull City, one of three appearances that season. At the season's end it was announced he would also spend the 2010–11 season with Wolves. Mujangi Bia failed to break into Wolves' first team plans during the next season, making just one league appearance, as a late substitute at Manchester City. He scored his only goal for Wolves in a 5–0 FA Cup victory over Championship team Doncaster Rovers. In April 2011 it was announced that he would transfer to Standard Liège on a three-year deal once the transfer window re-opened in the summer. The winger featured for Standard throughout the 2011–12 season as the club ended in fifth place. However, in August 2012, he was told he was no longer involved in the club's plans, and on 25 August signed for English Championship club Watford on a season-long loan deal, having already agreed to a long-term permanent contract; this will commence in summer 2013 if this option is exercised by Watford. He made his Watford debut on 28 August 2012 in their League Cup exit to eventual finalists Bradford. After making two league appearances for Watford in the early part of the season, Bia made his first league appearance since the back end of 2012 as a substitute in a 0–1 defeat to Barnsley on 16 March 2013. During the 2014/15 season Bia scored 14 and created a further 7 goals for Standard Liège. However, after a row with coach Slavoljub Muslin Bia found himself in the B team. During the summer of 2015 a proposed move to Bursaspor fell through after they announced the signing of Hungarian Dzsudzsák. Finally Bia signed a three-year deal with Swiss side Sion. On 10 May 2018, Bia helped Akhisar Belediyespor win their first professional trophy, the 2017–18 Turkish Cup. On February 5, 2018, Bia was fired by his club KSC Lokeren on "grounds of urgency".
