Despite dreams of playing in an outfield position, the 25-year-old started his career with hometown club Sint-Truiden.
In total Mignolet made 104 appearances for Sint-Truiden and contributed as the Belgian team achieved promotion to the top flight during the 2008-09 campaign by winning the second division title.
Remarkably, Simon actually scored a goal for the team during that season. In a match at Ronse in April 2009, the ‘keeper stepped up to attempt a penalty kick and converted the rebound after his initial effort was blocked.
Growing in confidence and developing an imposing presence as the last line of defence, Mignolet played 39 league matches the following year to help Sint-Truiden finish fifth and enter the end-of-season play-offs.