Mark de Kooker is appointed as the new head coach of FC Volendam O21. He was previously interim head coach of Alphense Boys and completed a training stint with Volendam's O19. De Kooker was from October 2024 to the summer of 2025 the final responsible person at the main team of Alphense Boys. He was promoted due to the departure of Marcel Valk. Edwin Vurens later supported him. A season earlier, he also took over temporarily from the retired Remco Tuinenburg. De Kooker is enthusiastic about his new role and says: 'I am proud to be the head coach of the O21 next season. The O21 is the last step in the training and my main task is to make players better every day and prepare them for the first team. I will go all out for it.' Technical director Patrick Busby is also enthusiastic about the new head coach and says: 'Mark is a very involved trainer who sets high standards for himself and others. We have confidence that he can prepare players well with the rest of the staff for the step to the first team.'