Prepare the fruit. Cut the pineapple and peaches into small chunks. Place the fruit into the blender.
Blend the mixture. Add the water and sugar to the blender with the fruit. Blend until the mixture is smooth.
Strain the agua fresca. Pour the blender mixture over a strainer or fine mesh sieve to separate the organic material from the liquid. Discard the fiberous material.
Serve over ice. Pour the agua fresca over ice and serve with a sprig of mint or a wedge of lime. Mangia!