Bring a large pot of water to a boil. Slowly add desired amount of tapioca pearls. Bring water back up to a simmer and cook about 20 to 30 minutes, stirring occasionally so pearls don't clump together. Rinse pearls in cold water once cooked.
In a large glass, add tapioca pearls, ice, coconut water, vanilla and sweetened condensed milk. Add coconut milk to taste. Stir and enjoy!