Bring 4 cups of water to a rolling boil in a medium pot. Once boiling vigorously, add the small tapioca pearls and stir immediately. Return to a boil and simmer for 20 minutes, stirring occasionally, until the pearls become completely clear and translucent.

If the pearls still show white centers after 20 minutes, turn off heat, cover the pot, and let them sit in the hot water for an additional 10 minutes until fully translucent.

Drain the cooked tapioca pearls completely, rinse under cold running water to cool them down, then place in a bowl of cold water and set aside.

Peel the mangoes and remove the pits by cutting around them. Reserve a generous handful of the nicest mango pieces for garnishing. Cut the remaining mango flesh into chunks for blending.

In a blender, combine the coconut milk, sweetened condensed milk, vanilla extract, and the larger portion of mango chunks. Blend until completely smooth and creamy. Transfer to a large mixing bowl.

For a cold dessert, refrigerate the mango mixture for at least 1 hour before serving. Note that cold temperatures may reduce sweetness, so taste and add more condensed milk if needed.

When ready to serve, drain the tapioca pearls from their water and stir them into the mango mixture. Scoop into individual serving bowls and top with the reserved mango chunks.