Add water and sugar to a pan. Heat over medium-high heat until it comes to a boil.
Reduce the heat to low. Add boba pearls to the pan and cook for 15 minutes.
Switch off the heat and add honey to the pan and stir well. Remove the pan from the heat and let the pearls soak in for 30 minutes.
Add blueberries, sugar, and water to a saucepan and cook over medium heat until the mixture comes to a boil, stirring frequently.
Gently mash the blueberries with the back of a spoon while cooking. Once the mixture comes to a boil, reduce the heat to low and cook the syrup for 10 minutes, stirring frequently.
Remove the pan from the heat and pass the syrup through a fine-mesh strainer.
Let the syrup cool down to room temperature.
Heat water in a pan. Once it comes to boil, switch off the stove and add 1 green tea bag.
Set the pan aside and let the tea brew for 10 minutes. Discard the tea bag and let the green tea come down to room temperature.
Pour the green tea into a tall glass. Pour milk and blueberry syrup over the green tea and stir well.
Take out the boba pearls from the cooking syrup using a slotted spoon and add them to the glass along with a few ice cubes. Serve immediately along with a large boba tea straw.