India, May 24 -- A couple of months after two children attacked Enna Pink's son with sticks at kindergarten, he began pleading with her to stay at home. "I didn't want to force him to go," says Ms Pink. She and her husband, who both worked at a startup, thought home-schooling would be a better fit for their son, who is "hyper-sensitive". But it is illegal in Germany, where they lived. So they moved to Costa Rica, where home-schooling is illegal for locals but there is little oversight for digital nomads.

Now her children, seven and four, do not follow lesson plans; instead they learn by playing outside, joining other children in local activities and travelling around the world. She thinks all this fosters curiosity and confidence. "We fe...