Bring water to a boil in a medium saucepan. Gradually add sago pearls, stirring occasionally, and cook until translucent, about 10–12 minutes.

Drain cooked sago in a fine mesh sieve and rinse under cold water. Set aside.

In a separate saucepan, combine coconut milk, sugar, and salt. Warm over low heat until sugar dissolves, without boiling.

Add cooked sago to the coconut milk mixture and stir gently. Let cool to room temperature.

Fold in diced mango pieces, reserving some for garnish.

Chill the Mango Sago in the refrigerator for at least 1 hour.

Serve in bowls or cups, garnished with fresh mint and remaining mango cubes.