Academic classes I know so far are third languages classes - French, spanish, italian... Other activities are all interest courses - ball games, music bands, etc.
Is your kid studying in local school now? Kinder or primary?
I cannot tell for others IS kids, as far as I know, some local Chinese ESF kids will attend tutor class of Chinese or Mandarin after school or on Saturday as the Chinese learning at school is not sufficient. For other subjects, they won't attend more tutor classes.
take my daughter as an example, she has less homework than conventional school and no examiniation, so most of her after-school activies are interest classes. except English (she was graduated from conventional kindergarten, she almost knew nothing about phonic..) and Abacus (relatively, the math that is covered in int'l is quite simple)
It all depends on the parents! My kid is also studying in an IS but some of his classmates have a lot of extra classes - tutor classes for Maths, English and Chinese/Mandarin. I think some of their parents are really crazy about academic results - just like their kids are studying local schools................. or maybe they really have a lot of money or their kids have a lot of extra energy Well, different parents have different styles - after all HK is a free society, right????????!!!!!!!!
I'm also a IS parent. I enrol my son into quite a lot of ECA becos he has no homework from school and he's the only son. So, I see the ECA for him more for killing time and socializing with friends.
His ECAs consist of both academic such as Mandarin and Abacus, also a lot of "interest" ones if you like to name them that way such as soccer, art, swimming, taekwondo and piano. But in fact, he likes Abacus a lot but he's not keen in piano and swimming (he like swimming himself but not guided by a coach). Therefore, I never categorize his ECA in this way.