Bring a pot of water to a boil. Add tapioca pearls and cook for 10-15 minutes, stirring often to prevent sticking.
Once the pearls are mostly translucent with tiny white centers, remove from heat and cover. Let sit for 10 minutes until fully cooked.
Drain and rinse under cold water to stop cooking.
In a bowl, combine coconut milk and condensed milk. Mix well.
Fold in cooked tapioca pearls and diced mango.
Chill in the refrigerator for at least 1 hour before serving.