Bring about 8-10 cups of water to a boil in a medium pot. Add the sago and simmer uncovered for 11-12 minutes. Turn off the heat, cover the pot, and let it sit for 5 minutes until the pearls turn translucent. Drain and rinse under cold water for 15-20 seconds to stop the cooking, then set aside.
1 cup sago
Cook the boba tapioca pearls according to the package directions until chewy, then drain and set aside.
1 cup boba tapioca pearls
Scoop the watermelon flesh into balls or cut into small cubes to get about 2-3 cups. Blend the remaining watermelon flesh until smooth, then strain out the pulp to get about 2.5-3 cups of juice.
½ watermelon
Grab a hollowed out watermelon half or a large bowl and add the coconut gel, boba tapioca pearls, watermelon balls, and sago. Pour in the sweetened condensed milk, evaporated milk, coconut milk, and watermelon juice, then stir until everything is well combined.
1 cup coconut gel, ⅓ cup sweetened condensed milk, 1 cup evaporated milk, 1.5 cups coconut milk
When ready to serve, scoop into small cups or bowls, top with ice, and enjoy immediately.
Ice cubes