It is compulsory for children to go for swimming lessons and to qualify by doing a diploma called “A, B, C” swemdiploma. It makes sense as there is so much water here in the Netherlands! They can start with the A-Diploma from age 4. A and B is compulsory, and C is optional. They have to do a certain amount of hours for the swimming lessons and the costs are approximately EUR11 per lesson for 45 minutes.