Bring water to a boil in a large pot. Add tapioca pearls only once the water is boiling. Stir and cook over medium-high heat for 15 minutes.
Turn off heat, cover, and let sit for 10–15 minutes until pearls are mostly translucent.
Drain and rinse pearls under cold water. Transfer to a bowl of cold water and set aside.
In a saucepan, heat milk and coconut milk until just boiling. Turn off heat and stir in 2 tablespoons honey. Let cool for 5–10 minutes.
Cut mangoes and cube the flesh. Reserve some cubes for texture.
Add about 1 1/4 cups mango flesh to a blender along with the milk mixture. Blend until smooth. Pour into a large bowl.
Drain tapioca pearls and toss with remaining 1 1/2 tablespoons honey.
Add tapioca pearls to the mango mixture and stir. Fold in mango chunks and sliced strawberries.
Taste and adjust sweetness if needed.
Chill for at least 2 hours before serving.