The market season opens every year in April with D'r Heëlesje Joarmaat. The next annual market is on Saturday 19 April 2025 from 9:00 - 17:00 in the centre of Heerlen. It is a large, atmospheric market that brings vendors from all over to Heerlen to sell their wares. Visitors can participate in special activities throughout the city centre, stroll past 400 market stalls and enjoy art, music and entertainment.