Preheat oven to 200 degrees F. Line a large rimmed baking sheet with a nonstick baking mat.

Puree mangoes, water and lemon juice in a blender until smooth. Pour into a medium saucepan and bring to a simmer over medium heat. Reduce heat to maintain a simmer and cook, partially covered, until reduced to about 2 cups puree, about 20 minutes.

Pour the puree onto the prepared baking sheet. With a rubber spatula, very evenly spread into a thin rectangle, no thicker than 1/8 inch thick.

Bake until dry to the touch, 4 to 6 hours. Let cool completely.

Transfer the fruit leather to a piece of parchment paper (or wax paper) about the same size. Leaving the parchment underneath, roll the fruit leather closed into a long cylinder. Using a sharp knife or scissors, cut into 2-inch wide strips.