Corn starch and tapioca starch can be substituted.

It should be possible to use tapioca starch instead of cornstarch, but it depends on what you are making. If you are making taro balls, it is very good to use tapioca starch instead of corn starch, because taro balls made from corn starch are more delicious than taro balls made from corn starch.

But if you are thickening the soup, you cannot replace it because tapioca starch is very sticky.